diff --git a/apps/api/scripts/reset-admin.ts b/apps/api/scripts/reset-admin.ts
index ec1675d..3bda451 100644
--- a/apps/api/scripts/reset-admin.ts
+++ b/apps/api/scripts/reset-admin.ts
@@ -51,16 +51,43 @@ function hashPassword(password: string): string {
 }
 
 // ── CLI arg parsing (no new deps — process.argv only) ───────────────────────────────────
-function parseArgs(argv: string[]): Record<string, string> {
-  const result: Record<string, string> = {};
+// WR-01: support both `--key=value` and `--key value`, and parse values EXPLICITLY rather
+// than inferring an empty string whenever the next token starts with '--'. The old heuristic
+// coerced `--password --foo` (and a legitimately `--`-prefixed or empty password) silently to
+// ''. Here, known value-taking flags (--username, --password) always consume the next token
+// verbatim as their value; the only boolean flag (--dry-run) takes no value. This keeps a
+// password that begins with '--', or an intentionally empty password, intact.
+const VALUE_FLAGS = new Set(['username', 'password']);
+const BOOLEAN_FLAGS = new Set(['dry-run']);
+
+function parseArgs(argv: string[]): Record<string, string | undefined> {
+  const result: Record<string, string | undefined> = {};
   for (let i = 0; i < argv.length; i++) {
     const arg = argv[i];
-    if (arg.startsWith('--')) {
-      const key = arg.slice(2);
-      const value = argv[i + 1] !== undefined && !argv[i + 1].startsWith('--') ? argv[i + 1] : '';
-      result[key] = value;
-      if (value) i++; // skip the value token
+    if (!arg.startsWith('--')) continue;
+
+    const eq = arg.indexOf('=');
+    if (eq !== -1) {
+      // `--key=value` form — value is everything after the first '=', taken verbatim
+      // (so `--password=--weird` and `--password=` both work correctly).
+      result[arg.slice(2, eq)] = arg.slice(eq + 1);
+      continue;
     }
+
+    const key = arg.slice(2);
+    if (BOOLEAN_FLAGS.has(key)) {
+      result[key] = ''; // presence-only flag; detected via hasOwnProperty
+      continue;
+    }
+    if (VALUE_FLAGS.has(key)) {
+      // Consume the NEXT token verbatim as the value — even if it starts with '--' or is
+      // empty. If there is no next token, record undefined (genuinely absent, not '').
+      result[key] = argv[i + 1];
+      if (i + 1 < argv.length) i++; // skip the consumed value token
+      continue;
+    }
+    // Unknown flag — record presence with no value (forward-compatible, no crash).
+    result[key] = '';
   }
   return result;
 }
@@ -120,7 +147,8 @@ try {
     // Existing local_credentials row — update password and ensure is_admin
     userId = lcRows[0].user_id;
     await conn.execute('UPDATE users SET is_admin = true, claimed = true WHERE id = ?', [userId]);
-    console.log(`[reset-admin] Found existing user id=${userId} for username="${username}"`);
+    // WR-01: do not echo the username — log only the resolved user id (no credential data).
+    console.log(`[reset-admin] Found existing user id=${userId}`);
   } else {
     // No existing row — insert a new user
     const displayName = username;
@@ -130,7 +158,8 @@ try {
       [displayName],
     );
     userId = (insertResult as unknown as { insertId: number }).insertId;
-    console.log(`[reset-admin] Created new user id=${userId} for username="${username}"`);
+    // WR-01: do not echo the username — log only the resolved user id.
+    console.log(`[reset-admin] Created new user id=${userId}`);
   }
 
   // ── Upsert local_credentials row ─────────────────────────────────────────────────────
@@ -142,7 +171,7 @@ try {
     [userId, username, passwordHash],
   );
 
-  console.log(`[reset-admin] Local credential upserted for user id=${userId} username="${username}"`);
+  console.log(`[reset-admin] Local credential upserted for user id=${userId}`);
   console.log(`[reset-admin] Done. User id=${userId} is now a local admin.`);
 } finally {
   await conn.end();
diff --git a/apps/api/src/auth/devBypass.ts b/apps/api/src/auth/devBypass.ts
index d810838..2f2671b 100644
--- a/apps/api/src/auth/devBypass.ts
+++ b/apps/api/src/auth/devBypass.ts
@@ -44,15 +44,32 @@ export const DEV_USER = {
   color: COLOR_PALETTE[0], // '#4A90D9' — first palette slot
 } as const;
 
+/**
+ * The shape stored on c.get('user') across the bypass, local-session, and OIDC paths.
+ *
+ * BL-04: oidcIss/oidcSub are NULLABLE. Local users have null OIDC fields, and
+ * localAuthMiddleware must NOT fabricate sentinel ('local'/String(id)) values — those
+ * share the uniqueness domain (uniq_oidc_identity) with real OIDC identities and could
+ * collide with a genuine (iss,sub) pair if ever persisted. DEV_USER carries non-null
+ * 'dev'/'dev-user' values and remains assignable to this widened shape.
+ */
+export interface ContextUser {
+  id: number;
+  oidcIss: string | null;
+  oidcSub: string | null;
+  displayName: string | null;
+  color: string;
+}
+
 /**
  * Extend Hono's ContextVariableMap so that c.get('user') / c.set('user', ...)
- * are statically typed throughout the app. The value type is the DEV_USER shape,
- * which is compatible with both the bypass path and any future app-level user object
- * stored on context (they share the same id/displayName/color subset).
+ * are statically typed throughout the app. The value type is ContextUser — the shape
+ * shared by the dev-bypass path, the local-session path (nullable oidc fields), and any
+ * future app-level user object stored on context.
  */
 declare module 'hono' {
   interface ContextVariableMap {
-    user: typeof DEV_USER;
+    user: ContextUser;
   }
 }
 
@@ -114,10 +131,36 @@ export function devSessionCookieMiddleware(): MiddlewareHandler {
   // LOCAL_SESSION_SECRET not set — bypass mode exempts the secret requirement
   // (assertLocalSessionSecretSet skips when DEV_AUTH_BYPASS=true), but we cannot
   // issue a cookie without it. Degrade gracefully so devAuthBypass still works.
-  if (!process.env.LOCAL_SESSION_SECRET) {
+  const secret = process.env.LOCAL_SESSION_SECRET;
+  if (!secret) {
     return async (_c, next) => next();
   }
 
+  // BL-01: do not treat "present" as "safe". The boot guard's length floor
+  // (assertLocalSessionSecretSet, >= 32 chars) is SKIPPED in bypass mode, so apply the
+  // same floor here before minting a real, signature-valid local-session JWT for DEV_USER
+  // (id=1). A short/forgeable secret must NOT issue a genuine session token. Degrade to a
+  // no-op so the cookie is never signed with a weak key.
+  if (secret.length < 32) {
+    console.warn(
+      '[devSessionCookieMiddleware] LOCAL_SESSION_SECRET is shorter than 32 characters — ' +
+        'refusing to issue a dev local-session cookie. Generate a strong value with ' +
+        'node scripts/generate-secrets.mjs.',
+    );
+    return async (_c, next) => next();
+  }
+
+  // BL-01: warn loudly if the secret is the well-known dev placeholder. A genuine,
+  // signature-valid session token minted under this known value is trivially forgeable
+  // if the same secret ever leaks into a non-bypass environment.
+  if (secret === 'dev-secret-change-me-0000000000000000') {
+    console.warn(
+      '[devSessionCookieMiddleware] LOCAL_SESSION_SECRET is the well-known dev placeholder. ' +
+        'This is acceptable ONLY for local dev/CI under DEV_AUTH_BYPASS — never reuse this ' +
+        'value in any non-bypass or shared environment.',
+    );
+  }
+
   // Bypass active + secret set: issue a real local-session cookie for DEV_USER
   // on each request that does not already carry one.
   return async (c, next) => {
diff --git a/apps/api/src/auth/linkNonceStore.ts b/apps/api/src/auth/linkNonceStore.ts
new file mode 100644
index 0000000..a0cc2df
--- /dev/null
+++ b/apps/api/src/auth/linkNonceStore.ts
@@ -0,0 +1,55 @@
+/**
+ * linkNonceStore.ts — single-use nonce store for the OIDC-link state (IN-04).
+ *
+ * POST /api/me/link-oidc mints a signed `state` JWT carrying a random `nonce` "to prevent
+ * replay". Previously the /callback handler never recorded or checked that nonce, so a
+ * captured state JWT was fully replayable within its 10-minute signature window — the nonce
+ * provided no actual protection (this underlies the BL-03 takeover concern).
+ *
+ * This in-memory store makes the nonce genuinely single-use:
+ *   - registerLinkNonce(nonce, expEpochSeconds): called when the state is issued.
+ *   - consumeLinkNonce(nonce): called on /callback; returns true exactly ONCE per nonce
+ *     (and only while unexpired), false on replay / unknown / expired.
+ *
+ * In-memory is sufficient for a single-process household deployment (same scope as the
+ * loginAttempts limiter). Expired entries are swept opportunistically on each access so the
+ * map stays bounded. If this app ever runs multi-process, move this to Redis.
+ */
+
+// nonce → expiry (epoch ms). Presence means "issued and not yet consumed".
+const issuedNonces = new Map<string, number>();
+
+function sweepExpired(now: number): void {
+  for (const [nonce, expiresAt] of issuedNonces) {
+    if (now >= expiresAt) issuedNonces.delete(nonce);
+  }
+}
+
+/**
+ * Record a freshly-issued link nonce as valid until expEpochSeconds (the state JWT's exp).
+ */
+export function registerLinkNonce(nonce: string, expEpochSeconds: number): void {
+  const now = Date.now();
+  sweepExpired(now);
+  issuedNonces.set(nonce, expEpochSeconds * 1000);
+}
+
+/**
+ * Consume a link nonce. Returns true exactly once for a known, unexpired nonce; false for
+ * any replay, unknown, or expired nonce. Single-use: the entry is deleted on first success.
+ */
+export function consumeLinkNonce(nonce: string): boolean {
+  const now = Date.now();
+  sweepExpired(now);
+  const expiresAt = issuedNonces.get(nonce);
+  if (expiresAt === undefined || now >= expiresAt) return false;
+  issuedNonces.delete(nonce); // single-use
+  return true;
+}
+
+/**
+ * Test-only: clear all issued nonces.
+ */
+export function _clearLinkNonces(): void {
+  issuedNonces.clear();
+}
diff --git a/apps/api/src/auth/localAuthMiddleware.ts b/apps/api/src/auth/localAuthMiddleware.ts
index b952137..65befe9 100644
--- a/apps/api/src/auth/localAuthMiddleware.ts
+++ b/apps/api/src/auth/localAuthMiddleware.ts
@@ -33,7 +33,7 @@ import { eq } from 'drizzle-orm';
 import { db } from '../db/client.js';
 import { users } from '../db/schema.js';
 import { verifyLocalSessionCookie } from './localSession.js';
-import type { DEV_USER } from './devBypass.js';
+import type { ContextUser } from './devBypass.js';
 
 /**
  * Returns a Hono MiddlewareHandler that:
@@ -81,17 +81,20 @@ export function localAuthMiddleware(): MiddlewareHandler {
       return;
     }
 
-    // Populate c.get('user') with the same shape as DEV_USER (devBypass.ts ContextVariableMap).
-    // oidcIss/oidcSub: local users have nullable oidcIss/oidcSub — use fallback strings so the
-    // shape is compatible with typeof DEV_USER at runtime. Cast required because ContextVariableMap
-    // is narrowed to the const DEV_USER literal type.
+    // Populate c.get('user') with the ContextUser shape (devBypass.ts ContextVariableMap).
+    // BL-04: keep oidcIss/oidcSub as NULL for local users — do NOT fabricate
+    // 'local'/String(id) sentinels. Those values share the uniq_oidc_identity uniqueness
+    // domain with real OIDC identities, so persisting them (e.g. a future upsertUser call
+    // using these context values) would let two local users collide or a local user shadow
+    // a genuine OIDC identity. ContextUser widens oidcIss/oidcSub to string | null so no
+    // cast is needed.
     c.set('user', {
       id: row.id,
-      oidcIss: row.oidcIss ?? 'local',
-      oidcSub: row.oidcSub ?? String(row.id),
+      oidcIss: row.oidcIss ?? null,
+      oidcSub: row.oidcSub ?? null,
       displayName: row.displayName ?? null,
       color: row.color ?? '#4A90D9',
-    } as typeof DEV_USER);
+    } satisfies ContextUser);
 
     await next();
   };
diff --git a/apps/api/src/auth/localCredentials.ts b/apps/api/src/auth/localCredentials.ts
index 7245fa4..ff11500 100644
--- a/apps/api/src/auth/localCredentials.ts
+++ b/apps/api/src/auth/localCredentials.ts
@@ -18,7 +18,31 @@
  * Max length: ~83 chars — fits in varchar(256) password_hash column
  */
 
-import { scryptSync, randomBytes, timingSafeEqual } from 'node:crypto';
+import { scrypt, randomBytes, timingSafeEqual } from 'node:crypto';
+import type { BinaryLike, ScryptOptions } from 'node:crypto';
+
+// WR-03: use the ASYNC scrypt (libuv threadpool) so password hashing does NOT block the
+// single Node event loop. scryptSync ran on the main thread, so a burst of unauthenticated
+// POST /local/login requests (each running scrypt N=16384, ~tens of ms of CPU, including the
+// always-run dummy-hash path) could pin the loop and stall ALL other API traffic — a cheap
+// unauthenticated DoS. This async wrapper offloads the CPU to the threadpool, preserving the
+// timing-defense property while keeping the loop responsive.
+//
+// A hand-rolled Promise wrapper is used (rather than promisify) because promisify's typings
+// do not cover the options-carrying scrypt overload (N/r/p).
+function scryptAsync(
+  password: BinaryLike,
+  salt: BinaryLike,
+  keylen: number,
+  options: ScryptOptions,
+): Promise<Buffer> {
+  return new Promise((resolve, reject) => {
+    scrypt(password, salt, keylen, options, (err, derivedKey) => {
+      if (err) reject(err);
+      else resolve(derivedKey);
+    });
+  });
+}
 
 // OWASP-compatible scrypt parameters for password hashing
 const SCRYPT_N = 16384; // CPU/memory cost factor (2^14)
@@ -36,12 +60,15 @@ const KEY_LEN = 32; // 256-bit derived key output
  * the hash without relying on hardcoded constants — supports future parameter
  * migration without a DB schema change.
  *
- * NOTE: scryptSync blocks the event loop. For a 2-person household with
- * infrequent logins this is acceptable. Use promisify(scrypt) if async is needed.
+ * WR-03: async — scrypt runs on the libuv threadpool, not the event loop.
  */
-export function hashPassword(password: string): string {
+export async function hashPassword(password: string): Promise<string> {
   const salt = randomBytes(16);
-  const hash = scryptSync(password, salt, KEY_LEN, { N: SCRYPT_N, r: SCRYPT_R, p: SCRYPT_P });
+  const hash = await scryptAsync(password, salt, KEY_LEN, {
+    N: SCRYPT_N,
+    r: SCRYPT_R,
+    p: SCRYPT_P,
+  });
   return [
     'scrypt',
     SCRYPT_N,
@@ -66,9 +93,12 @@ export function hashPassword(password: string): string {
  *     scrypt parameter error — safe to call with untrusted input.
  *   - Never logs the candidate password.
  *
- * @returns true if candidate matches the stored hash; false otherwise (incl. errors)
+ * WR-03: async — scrypt runs on the libuv threadpool, not the event loop.
+ *
+ * @returns Promise<true> if candidate matches the stored hash; Promise<false> otherwise
+ *          (including all parse/format/crypto errors — never rejects).
  */
-export function verifyPassword(storedEncoded: string, candidate: string): boolean {
+export async function verifyPassword(storedEncoded: string, candidate: string): Promise<boolean> {
   try {
     const parts = storedEncoded.split('$');
     if (parts.length !== 6) return false;
@@ -76,7 +106,7 @@ export function verifyPassword(storedEncoded: string, candidate: string): boolea
     const salt = Buffer.from(saltB64, 'base64url');
     const storedHash = Buffer.from(hashB64, 'base64url');
     if (salt.length === 0 || storedHash.length === 0) return false;
-    const candidateHash = scryptSync(candidate, salt, storedHash.length, {
+    const candidateHash = await scryptAsync(candidate, salt, storedHash.length, {
       N: Number(n),
       r: Number(r),
       p: Number(p),
diff --git a/apps/api/src/auth/localSession.ts b/apps/api/src/auth/localSession.ts
index 1308e8b..39017ec 100644
--- a/apps/api/src/auth/localSession.ts
+++ b/apps/api/src/auth/localSession.ts
@@ -27,8 +27,15 @@ import type { Context } from 'hono';
 // Cookie name must be distinct from the OIDC cookie 'oidc-auth' (Pitfall 4)
 const COOKIE_NAME = 'local-session';
 
-// Session max age: default 1 day (86400s); configurable via LOCAL_SESSION_EXPIRES env
-const SESSION_MAX_AGE_SECONDS = Number(process.env.LOCAL_SESSION_EXPIRES ?? 86400);
+// Session max age: default 1 day (86400s); configurable via LOCAL_SESSION_EXPIRES env.
+// IN-01: validate the coercion. A malformed value yields NaN, which would produce a JWT
+// with exp = now + NaN (→ NaN) and a cookie maxAge: NaN — making verify behaviour
+// "always expired" or "never expires" depending on the lib's NaN handling. Fall back to
+// the 86400s default for any non-finite or non-positive value.
+const SESSION_MAX_AGE_SECONDS = (() => {
+  const n = Number(process.env.LOCAL_SESSION_EXPIRES ?? 86400);
+  return Number.isFinite(n) && n > 0 ? n : 86400;
+})();
 
 /**
  * Issue a signed local-session JWT cookie for the given userId.
@@ -98,9 +105,13 @@ export function clearLocalSessionCookie(c: Context): void {
   deleteCookie(c, COOKIE_NAME, {
     path: '/',
     httpOnly: true,
-    // Use secure:true for delete (browsers only accept the attribute in matching context)
-    // In practice this is safe because logout should happen over HTTPS in production.
-    secure: true,
+    // BL-02: mirror the issue-time `secure` logic. issueLocalSessionCookie sets
+    // secure:false over plain HTTP (non-production), and a browser will REJECT a
+    // Secure delete-cookie sent over HTTP — so a hard-coded secure:true left the
+    // local-session cookie uncleared on every non-HTTPS deployment (local dev and any
+    // HTTP-only self-host), leaving the user "logged in" after logout. Match the
+    // context so the deletion cookie is accepted.
+    secure: process.env.NODE_ENV === 'production',
     sameSite: 'Lax',
   });
 }
diff --git a/apps/api/src/auth/oidcConfig.ts b/apps/api/src/auth/oidcConfig.ts
new file mode 100644
index 0000000..eaafdf3
--- /dev/null
+++ b/apps/api/src/auth/oidcConfig.ts
@@ -0,0 +1,91 @@
+/**
+ * oidcConfig.ts — centralized "is OIDC configured" resolution + endpoint discovery.
+ *
+ * WR-04: three sites previously had independent notions of whether OIDC is configured:
+ *   - routes/authMode.ts          → OIDC_ISSUER env OR app_config.oidc_issuer
+ *   - auth/middleware.ts          → injects issuer/client-id/external-url from app_config
+ *   - routes/me.ts (link-oidc)    → ONLY env (OIDC_ISSUER && OIDC_CLIENT_ID && OIDC_REDIRECT_URI)
+ *
+ * The me.ts divergence meant a wizard-configured-but-not-restarted instance reported
+ * oidcEnabled:true from /api/auth/mode (and showed the "Link OIDC" button) but link-oidc
+ * returned authorizationUrl:null. This helper makes the env-OR-app_config resolution a
+ * single source of truth.
+ *
+ * WR-02: me.ts also hardcoded Authelia's `/api/oidc/authorization` path. The project's
+ * design is to discover endpoints from the issuer's /.well-known/openid-configuration
+ * document (the whole reason @hono/oidc-auth is used). discoverAuthorizationEndpoint()
+ * resolves the real authorization_endpoint so any RFC-compliant provider works.
+ */
+
+import { eq } from 'drizzle-orm';
+import { db } from '../db/client.js';
+import { appConfig } from '../db/schema.js';
+
+export interface ResolvedOidcConfig {
+  issuer: string;
+  clientId: string;
+  redirectUri: string;
+}
+
+/**
+ * Read a single app_config value (or null when absent).
+ */
+async function readAppConfig(key: string): Promise<string | null> {
+  const [row] = await db
+    .select({ value: appConfig.value })
+    .from(appConfig)
+    .where(eq(appConfig.key, key))
+    .limit(1);
+  return row?.value ?? null;
+}
+
+/**
+ * Resolve issuer + clientId + redirectUri using env first, then app_config (WR-04).
+ *
+ * Returns null when any of the three cannot be resolved from EITHER source — i.e. OIDC is
+ * not (fully) configured, so no authorization URL can be built. The redirect URI is taken
+ * from OIDC_REDIRECT_URI when present, else derived from the external app URL
+ * (OIDC_AUTH_EXTERNAL_URL env or app_config.app_external_url) as `${externalUrl}/callback`,
+ * matching the middleware's redirect-uri construction.
+ */
+export async function resolveOidcConfig(): Promise<ResolvedOidcConfig | null> {
+  const issuer = process.env.OIDC_ISSUER ?? (await readAppConfig('oidc_issuer'));
+  const clientId = process.env.OIDC_CLIENT_ID ?? (await readAppConfig('oidc_client_id'));
+
+  let redirectUri = process.env.OIDC_REDIRECT_URI ?? null;
+  if (!redirectUri) {
+    const externalUrl =
+      process.env.OIDC_AUTH_EXTERNAL_URL ?? (await readAppConfig('app_external_url'));
+    if (externalUrl) {
+      redirectUri = `${externalUrl.replace(/\/$/, '')}/callback`;
+    }
+  }
+
+  if (!issuer || !clientId || !redirectUri) return null;
+  return { issuer, clientId, redirectUri };
+}
+
+/**
+ * Discover the provider's authorization_endpoint from its OIDC discovery document (WR-02).
+ *
+ * Fetches `${issuer}/.well-known/openid-configuration` (5s timeout, matching the setup
+ * wizard's validate/oidc step) and returns the `authorization_endpoint` URL. Returns null
+ * on any network error, non-2xx, or missing field — callers treat null as "cannot build
+ * the authorization URL" and degrade gracefully (the PWA disables the Link button).
+ */
+export async function discoverAuthorizationEndpoint(issuer: string): Promise<string | null> {
+  try {
+    const res = await fetch(`${issuer.replace(/\/$/, '')}/.well-known/openid-configuration`, {
+      signal: AbortSignal.timeout(5000),
+    });
+    if (!res.ok) return null;
+    const doc = (await res.json()) as { authorization_endpoint?: unknown };
+    return typeof doc.authorization_endpoint === 'string' ? doc.authorization_endpoint : null;
+  } catch (err) {
+    console.error(
+      '[oidcConfig/discoverAuthorizationEndpoint]',
+      err instanceof Error ? err.message : String(err),
+    );
+    return null;
+  }
+}
diff --git a/apps/api/src/index.ts b/apps/api/src/index.ts
index 6616545..d1b2891 100644
--- a/apps/api/src/index.ts
+++ b/apps/api/src/index.ts
@@ -20,6 +20,8 @@ import {
 } from './auth/middleware.js';
 import { devAuthBypass, devSessionCookieMiddleware } from './auth/devBypass.js';
 import { localAuthMiddleware } from './auth/localAuthMiddleware.js';
+import { verifyLocalSessionCookie } from './auth/localSession.js';
+import { consumeLinkNonce } from './auth/linkNonceStore.js';
 import { persistSessionCookie } from './auth/persistSessionCookie.js';
 import { startBrokerPoller } from './broker/poller.js';
 import { startOutboxWorker, initOutboxTrigger } from './broker/outboxWorker.js';
@@ -58,6 +60,7 @@ app.get('/callback', async (c) => {
   // Attempt to extract linkUserId from the signed state param BEFORE processOAuthCallback
   // consumes it. The state param may be our signed JWT (link mode) or a random string (normal).
   let linkUserId: number | null = null;
+  let linkNonce: string | null = null;
   const rawState = c.req.query('state');
   if (rawState) {
     const secret = process.env.LOCAL_SESSION_SECRET;
@@ -66,6 +69,7 @@ app.get('/callback', async (c) => {
         const payload = await Jwt.verify(rawState, secret, 'HS256');
         if (typeof payload.linkUserId === 'number') {
           linkUserId = payload.linkUserId;
+          linkNonce = typeof payload.nonce === 'string' ? payload.nonce : null;
         }
       } catch {
         // Not our signed link state — normal OIDC callback, proceed normally.
@@ -79,10 +83,41 @@ app.get('/callback', async (c) => {
   // Link mode: after session is established, bind the OIDC identity to the local user.
   if (linkUserId !== null) {
     try {
+      // IN-04: enforce SINGLE USE of the link nonce. The signed state JWT is otherwise
+      // replayable for its full 10-minute signature lifetime; consuming the nonce here means
+      // a captured state can be used at most once. A replay (already-consumed), unknown, or
+      // expired nonce is rejected before any binding occurs.
+      if (!linkNonce || !consumeLinkNonce(linkNonce)) {
+        console.warn('[callback] OIDC-link rejected: link nonce missing, replayed, or expired.');
+        return c.redirect('/?error=oidc-link-conflict');
+      }
+
+      // BL-03: cross-check that the local session completing this callback is the SAME
+      // user the link flow was initiated for. The signed `state` JWT proves the state was
+      // minted by POST /api/me/link-oidc, but NOT that the person finishing the OIDC login
+      // is that user. Without this check, an attacker who gets a victim to complete an OIDC
+      // login while replaying a still-valid (10-min) captured link state would bind the
+      // ATTACKER's OIDC identity onto the VICTIM's account (account takeover). Require the
+      // initiating local session to still be present and to match linkUserId.
+      const sessionUserId = await verifyLocalSessionCookie(c);
+      if (sessionUserId !== linkUserId) {
+        console.warn(
+          '[callback] OIDC-link rejected: local session does not match link state (possible replay).',
+        );
+        return c.redirect('/?error=oidc-link-conflict');
+      }
+
       const auth = await getAuth(c);
       if (auth) {
         const iss = (auth.iss as string | undefined) ?? '';
         const sub = auth.sub ?? '';
+        // BL-03: never bind on a blank/partial identity. linkOidcToUser writes oidc_iss/
+        // oidc_sub AND deletes the user's local_credentials — binding empty iss/sub would
+        // both corrupt identity and lock the user out of BOTH auth methods. Reject instead.
+        if (!iss || !sub) {
+          console.warn('[callback] OIDC-link rejected: empty iss/sub from getAuth.');
+          return c.redirect('/?error=oidc-link-conflict');
+        }
         await linkOidcToUser(linkUserId, iss, sub);
         // On success: user is now OIDC-only; normal redirect via callbackResponse proceeds.
       }
diff --git a/apps/api/src/routes/admin.ts b/apps/api/src/routes/admin.ts
index 968bdd3..aa2c183 100644
--- a/apps/api/src/routes/admin.ts
+++ b/apps/api/src/routes/admin.ts
@@ -35,6 +35,7 @@ import {
   CredentialValidationError,
 } from '../broker/credentialSync.js';
 import { hashPassword } from '../auth/localCredentials.js';
+import { resetLoginAttempts } from './localAuth.js';
 import { COLOR_PALETTE } from '../auth/user.js';
 // Side-effect import: brings in the ContextVariableMap augmentation for c.get('user')
 import '../auth/devBypass.js';
@@ -77,6 +78,19 @@ const noEchoHook = (result: { success: boolean }, c: Context) => {
   }
 };
 
+/**
+ * WR-07: strictly parse a positive-integer route param. parseInt('12abc', 10) returns 12
+ * and passes an isNaN guard, silently accepting malformed ids. Number('12abc') is NaN, so
+ * Number.isInteger(Number(raw)) rejects trailing garbage. Returns null for anything that is
+ * not a whole positive integer (empty, '12abc', '1.5', '-3', '0', etc.) so the caller can 400.
+ */
+function parsePositiveIntParam(raw: string | undefined): number | null {
+  if (raw === undefined || raw.trim() === '') return null;
+  const n = Number(raw);
+  if (!Number.isInteger(n) || n <= 0) return null;
+  return n;
+}
+
 // ---------------------------------------------------------------------------
 // GET /api/admin/members
 //
@@ -140,6 +154,10 @@ adminRouter.post(
       COLOR_PALETTE.find((c) => !usedColors.has(c)) ??
       COLOR_PALETTE[usedColors.size % COLOR_PALETTE.length];
 
+    // WR-03: hash the initial password BEFORE opening the transaction so the (now async,
+    // threadpool) scrypt work does not hold the DB transaction open for its duration.
+    const initialPasswordHash = await hashPassword(initialPassword);
+
     try {
       let newUserId: number;
 
@@ -162,7 +180,7 @@ adminRouter.post(
         await tx.insert(localCredentials).values({
           userId: newUserId,
           username,
-          passwordHash: hashPassword(initialPassword),
+          passwordHash: initialPasswordHash,
         });
       });
 
@@ -212,17 +230,18 @@ adminRouter.post(
   '/members/:id/password',
   zValidator('json', resetPasswordSchema, noEchoHook),
   async (c) => {
-    const targetId = parseInt(c.req.param('id'), 10);
-    if (isNaN(targetId)) {
+    const targetId = parsePositiveIntParam(c.req.param('id'));
+    if (targetId === null) {
       return c.json({ error: 'Invalid member id' }, 400);
     }
 
     const { newPassword } = c.req.valid('json');
     // T-19-06: NEVER log newPassword or the request body
 
-    // Verify the target user has a local_credentials row (404 if not)
+    // Verify the target user has a local_credentials row (404 if not).
+    // Also read the username so we can clear any login lockout for it (CR-04).
     const [credRow] = await db
-      .select({ id: localCredentials.id })
+      .select({ id: localCredentials.id, username: localCredentials.username })
       .from(localCredentials)
       .where(eq(localCredentials.userId, targetId))
       .limit(1);
@@ -234,9 +253,14 @@ adminRouter.post(
     try {
       await db
         .update(localCredentials)
-        .set({ passwordHash: hashPassword(newPassword) })
+        .set({ passwordHash: await hashPassword(newPassword) })
         .where(eq(localCredentials.userId, targetId));
 
+      // CR-04: an admin password reset must immediately clear any rate-limit / lockout
+      // state for this username, so a locked-out member regains access at once rather than
+      // waiting for the TTL. The lockout is keyed on username (not member id).
+      resetLoginAttempts(credRow.username);
+
       return c.json({ ok: true }, 200);
     } catch (err) {
       console.error(
@@ -305,8 +329,8 @@ adminRouter.get('/calendars', async (c) => {
 // ---------------------------------------------------------------------------
 
 adminRouter.put('/calendars/:id/shared', async (c) => {
-  const targetId = parseInt(c.req.param('id'), 10);
-  if (isNaN(targetId)) {
+  const targetId = parsePositiveIntParam(c.req.param('id'));
+  if (targetId === null) {
     return c.json({ error: 'Invalid calendar id' }, 400);
   }
 
diff --git a/apps/api/src/routes/localAuth.ts b/apps/api/src/routes/localAuth.ts
index 5069c99..68bd47e 100644
--- a/apps/api/src/routes/localAuth.ts
+++ b/apps/api/src/routes/localAuth.ts
@@ -14,8 +14,16 @@
  *   - Dummy-hash timing defense: verifyPassword is always called, even for unknown usernames,
  *     to prevent timing-oracle username enumeration attacks (T-19-12 / RESEARCH Pitfall 2).
  *   - Same 401 body for wrong password AND unknown username — no field discrimination (T-19-12).
- *   - Per-IP in-memory rate-limiting: 5 failures → 429; 10 failures → 423 (T-19-11).
- *   - Lockout (423) cleared only by admin password reset — no self-service unlock.
+ *   - Per-USERNAME in-memory rate-limiting: 5 failures → 429; 10 failures → 423 (T-19-11).
+ *   - Lockout (423) auto-expires after LOCKOUT_TTL_MS (CR-04) so a single attacker cannot
+ *     permanently deny login for the whole household, and no process restart is needed to
+ *     recover. Admin password reset still clears it immediately (resetLoginAttempts).
+ *
+ * CR-04: the limiter is keyed on the submitted username, NOT the client IP. In this
+ * deployment all household traffic egresses the Pangolin tunnel with the same
+ * X-Forwarded-For first hop, so IP-keying made one bad actor (or one fat-fingered user)
+ * able to lock out every member, and X-Forwarded-For is attacker-spoofable. Username-keying
+ * scopes the lockout to the identity actually under attack and the TTL makes it self-healing.
  */
 
 import { Hono } from 'hono';
@@ -52,61 +60,122 @@ const loginSchema = z.object({
 });
 
 // ---------------------------------------------------------------------------
-// Per-IP rate-limiting state (in-memory Map — household scale, no Redis needed).
+// Per-USERNAME rate-limiting state (in-memory Map — household scale, no Redis needed).
 //
-// State shape per IP: { count, lockedUntil (epoch ms), lockedOut (bool) }
+// State shape per username: { count, lockedUntil (epoch ms), lockedOut (bool), lockedAt (epoch ms) }
 //   count >= RATE_WINDOW_FAILURES AND Date.now() < lockedUntil → 429
-//   count >= LOCKOUT_FAILURES → 423 (permanent until admin reset)
+//   count >= LOCKOUT_FAILURES → 423 (until LOCKOUT_TTL_MS elapses OR admin reset)
 //   Success → delete entry (clears counter)
 //
 // RATE_WINDOW_FAILURES: 5 failures → 60s cooldown (429)
 // LOCKOUT_FAILURES:    10 failures → account locked (423)
+// LOCKOUT_TTL_MS:      15 min after which a 423 lockout auto-expires (CR-04)
+//
+// CR-04: keyed on the validated username (not the client IP) so a lockout is scoped to
+// the identity under attack, and self-heals after LOCKOUT_TTL_MS without a restart.
 // ---------------------------------------------------------------------------
 
-export const loginAttempts = new Map<string, { count: number; lockedUntil: number; lockedOut: boolean }>();
+export const loginAttempts = new Map<
+  string,
+  { count: number; lockedUntil: number; lockedOut: boolean; lockedAt: number }
+>();
 
 const RATE_WINDOW_FAILURES = 5;
 const RATE_WINDOW_SECS = 60;
 const LOCKOUT_FAILURES = 10;
+const LOCKOUT_TTL_MS = 15 * 60 * 1000; // CR-04: 423 lockout auto-expires after 15 minutes
+
+/**
+ * Immediately clear any rate-limit / lockout state for a username (CR-04).
+ *
+ * Called by the admin password-reset path so a reset is an instant unlock and the
+ * lockout is not "unrecoverable without a process restart". Safe to call for an
+ * unknown username (no-op). Normalizes the username the same way the login schema
+ * does (trim) so the key matches what the limiter stored.
+ */
+export function resetLoginAttempts(username: string): void {
+  loginAttempts.delete(username.trim());
+}
+
+/**
+ * IN-03: evict stale rate-limit entries to bound the in-memory map size.
+ *
+ * An entry is stale (and safe to drop) when it is neither inside an active rate-limit
+ * window nor inside an active lockout TTL:
+ *   - locked-out entries expire LOCKOUT_TTL_MS after lockedAt
+ *   - non-locked entries expire once their lockedUntil window has passed
+ *
+ * Called opportunistically at the top of each login request. Dropping an entry is
+ * behaviourally identical to the entry having naturally expired, so eviction never
+ * weakens the brute-force defense — it only reclaims memory for identities no longer
+ * under active rate-limiting.
+ */
+function evictStaleLoginAttempts(now: number): void {
+  for (const [k, v] of loginAttempts) {
+    const lockoutExpired = v.lockedOut ? now - v.lockedAt >= LOCKOUT_TTL_MS : true;
+    const windowExpired = now >= v.lockedUntil;
+    if (lockoutExpired && windowExpired) {
+      loginAttempts.delete(k);
+    }
+  }
+}
 
 // Pre-computed dummy hash used to run verifyPassword on unknown-username paths
 // (timing defense — prevents timing-oracle username enumeration, RESEARCH Pitfall 2).
-// Computed once at module load time; the actual value is never used for auth.
-const DUMMY_HASH = hashPassword('dummy-constant-time-filler-xyzzy');
+// WR-03: hashPassword is now async. Kick off the computation once at module load and keep
+// the PROMISE; the login handler awaits it. The value is never used for auth — only to make
+// the unknown-username path perform the same scrypt work as the known-username path.
+const dummyHashPromise: Promise<string> = hashPassword('dummy-constant-time-filler-xyzzy');
 
 // ---------------------------------------------------------------------------
 // POST /local/login  →  POST /api/auth/local/login
 // ---------------------------------------------------------------------------
 
 localAuthRouter.post('/local/login', zValidator('json', loginSchema, noEchoHook), async (c) => {
-  // Derive client IP from Pangolin-set X-Forwarded-For header; fall back to host header.
-  const ip = c.req.header('x-forwarded-for')?.split(',')[0]?.trim()
-    ?? c.req.raw.headers.get('host')
-    ?? 'unknown';
+  // CR-04: the rate-limit / lockout key is the validated, normalized username — NOT the
+  // client IP. zValidator has already run, so c.req.valid('json') is available here.
+  const { username, password } = c.req.valid('json');
+  const key = username; // loginSchema .trim()s the username; the map key matches resetLoginAttempts
 
-  const attempt = loginAttempts.get(ip);
+  const now = Date.now();
+  // IN-03: opportunistically reclaim memory from entries that are no longer actively
+  // rate-limited or locked out. Cheap at household scale; bounds the map under input churn.
+  evictStaleLoginAttempts(now);
+  const attempt = loginAttempts.get(key);
 
-  // 423: account locked (>= LOCKOUT_FAILURES total failures, admin must reset)
-  // Check lockedOut FIRST — lockout takes precedence over rate window.
+  // 423: account locked (>= LOCKOUT_FAILURES failures). CR-04: the lockout auto-expires
+  // after LOCKOUT_TTL_MS so a single attacker cannot deny login indefinitely and no restart
+  // is required to recover. On expiry, drop the entry so the next attempt starts clean.
   if (attempt?.lockedOut) {
-    return c.json({ error: 'Account locked' }, 423);
+    if (now - attempt.lockedAt >= LOCKOUT_TTL_MS) {
+      loginAttempts.delete(key);
+    } else {
+      return c.json({ error: 'Account locked' }, 423);
+    }
   }
 
+  // Re-read after a possible expiry-delete above.
+  const live = loginAttempts.get(key);
+
   // 429: rate window — >= RATE_WINDOW_FAILURES failures within the cooldown window.
   // Increment the counter even on 429 so continued brute-force accumulates toward lockout.
-  if (attempt && attempt.count >= RATE_WINDOW_FAILURES && Date.now() < attempt.lockedUntil) {
-    attempt.count += 1;
-    attempt.lockedUntil = Date.now() + RATE_WINDOW_SECS * 1000;
-    attempt.lockedOut = attempt.count >= LOCKOUT_FAILURES;
-    loginAttempts.set(ip, attempt);
-    if (attempt.lockedOut) {
+  if (live && live.count >= RATE_WINDOW_FAILURES && now < live.lockedUntil) {
+    live.count += 1;
+    // WR-06: do NOT extend lockedUntil here. This request was itself REJECTED by the window;
+    // re-arming the cooldown on every blocked attempt let an attacker who keeps hammering the
+    // endpoint slide the window forward forever, so a legitimate user behind the same identity
+    // could never get back in even after pausing. The window stays anchored to when it was
+    // first armed (in the failure path below); it expires on schedule regardless of rejected
+    // traffic. The lockout (423) still triggers once the failure count crosses the threshold.
+    live.lockedOut = live.count >= LOCKOUT_FAILURES;
+    if (live.lockedOut && live.lockedAt === 0) live.lockedAt = now;
+    loginAttempts.set(key, live);
+    if (live.lockedOut) {
       return c.json({ error: 'Account locked' }, 423);
     }
     return c.json({ error: 'Too many attempts' }, 429);
   }
 
-  const { username, password } = c.req.valid('json');
-
   // Look up local_credentials by username
   let cred: { userId: number; passwordHash: string } | undefined;
   try {
@@ -124,23 +193,25 @@ localAuthRouter.post('/local/login', zValidator('json', loginSchema, noEchoHook)
   // ALWAYS run verifyPassword — even for unknown usernames — to prevent timing-oracle
   // username enumeration (T-19-12 / RESEARCH Pitfall 2). Use a pre-computed dummy hash
   // so the scrypt work is always performed regardless of whether username was found.
+  // WR-03: verifyPassword is async (threadpool scrypt) — await it.
   const valid = cred
-    ? verifyPassword(cred.passwordHash, password)
-    : verifyPassword(DUMMY_HASH, password);
+    ? await verifyPassword(cred.passwordHash, password)
+    : await verifyPassword(await dummyHashPromise, password);
 
   if (!valid || !cred) {
-    // Increment failure counter
-    const cur = loginAttempts.get(ip) ?? { count: 0, lockedUntil: 0, lockedOut: false };
+    // Increment failure counter (keyed on username)
+    const cur = loginAttempts.get(key) ?? { count: 0, lockedUntil: 0, lockedOut: false, lockedAt: 0 };
     cur.count += 1;
     cur.lockedUntil = Date.now() + RATE_WINDOW_SECS * 1000;
     cur.lockedOut = cur.count >= LOCKOUT_FAILURES;
-    loginAttempts.set(ip, cur);
+    if (cur.lockedOut && cur.lockedAt === 0) cur.lockedAt = Date.now();
+    loginAttempts.set(key, cur);
     // Same 401 body for wrong password AND unknown username — no field discrimination (T-19-12)
     return c.json({ error: 'Invalid credentials' }, 401);
   }
 
   // Success: clear failure counter, issue the local-session JWT cookie, return ok
-  loginAttempts.delete(ip);
+  loginAttempts.delete(key);
   try {
     await issueLocalSessionCookie(c, cred.userId);
   } catch (err) {
diff --git a/apps/api/src/routes/me.ts b/apps/api/src/routes/me.ts
index 6587312..3cf8961 100644
--- a/apps/api/src/routes/me.ts
+++ b/apps/api/src/routes/me.ts
@@ -41,6 +41,8 @@ import {
   CredentialValidationError,
 } from '../broker/credentialSync.js';
 import { hashPassword, verifyPassword } from '../auth/localCredentials.js';
+import { resolveOidcConfig, discoverAuthorizationEndpoint } from '../auth/oidcConfig.js';
+import { registerLinkNonce } from '../auth/linkNonceStore.js';
 // Side-effect import: brings in the ContextVariableMap augmentation for c.get('user')
 import '../auth/devBypass.js';
 
@@ -254,16 +256,21 @@ meRouter.post(
       return c.json({ error: 'No local credential found' }, 404);
     }
 
-    // T-19-07: verify current password before any update
-    const isCorrect = verifyPassword(credRow.passwordHash, currentPassword);
+    // T-19-07: verify current password before any update (WR-03: async scrypt)
+    const isCorrect = await verifyPassword(credRow.passwordHash, currentPassword);
     if (!isCorrect) {
-      return c.json({ error: 'Current password incorrect' }, 401);
+      // CR-03: return 403 (NOT 401) for a wrong current password. The PWA's global
+      // MutationCache treats any 401 as "session expired" and arms the re-auth
+      // interstitial / login redirect — so a 401 here would force-log-out a user who
+      // merely mistyped their current password. 403 is in-app authorization-failure and
+      // lets the client surface "current password incorrect" without dropping the session.
+      return c.json({ error: 'Current password incorrect' }, 403);
     }
 
     try {
       await db
         .update(localCredentials)
-        .set({ passwordHash: hashPassword(newPassword) })
+        .set({ passwordHash: await hashPassword(newPassword) })
         .where(eq(localCredentials.userId, currentUserId));
 
       return c.json({ ok: true }, 200);
@@ -313,28 +320,37 @@ meRouter.post('/link-oidc', async (c) => {
   // T-19-09: nonce prevents state replay attacks (each link attempt gets a fresh nonce)
   const nonce = randomBytes(16).toString('hex');
   const now = Math.floor(Date.now() / 1000);
+  const exp = now + 600; // 10-minute window
   const signedState = await Jwt.sign(
-    { linkUserId: currentUserId, nonce, iat: now, exp: now + 600 }, // 10-minute window
+    { linkUserId: currentUserId, nonce, iat: now, exp },
     secret,
     'HS256',
   );
 
-  // Build the OIDC authorization URL if OIDC is configured (else return null — PWA disables button)
-  const issuer = process.env.OIDC_ISSUER ?? null;
-  const clientId = process.env.OIDC_CLIENT_ID ?? null;
-  const redirectUri = process.env.OIDC_REDIRECT_URI ?? null;
+  // IN-04: record the nonce so /callback can enforce SINGLE USE. Without this the signed
+  // state JWT is fully replayable for its 10-minute signature lifetime and the nonce is
+  // decorative. registerLinkNonce keeps it valid only until the state's own exp.
+  registerLinkNonce(nonce, exp);
 
+  // Build the OIDC authorization URL if OIDC is configured (else return null — PWA disables button).
+  // WR-04: resolve issuer/clientId/redirectUri from env-OR-app_config (single source of truth,
+  // consistent with /api/auth/mode and the OIDC fallback middleware) so a wizard-configured
+  // instance does not report oidcEnabled:true while returning authorizationUrl:null here.
+  // WR-02: discover the authorization_endpoint from the provider's discovery document instead
+  // of hardcoding Authelia's /api/oidc/authorization path.
   let authorizationUrl: string | null = null;
-  if (issuer && clientId && redirectUri) {
-    // Construct the authorization URL. plan 19-03 will handle the full PKCE flow;
-    // for now encode the signed state so the callback can read linkUserId.
-    const url = new URL(`${issuer.replace(/\/$/, '')}/api/oidc/authorization`);
-    url.searchParams.set('response_type', 'code');
-    url.searchParams.set('client_id', clientId);
-    url.searchParams.set('redirect_uri', redirectUri);
-    url.searchParams.set('scope', 'openid profile email');
-    url.searchParams.set('state', signedState);
-    authorizationUrl = url.toString();
+  const oidc = await resolveOidcConfig();
+  if (oidc) {
+    const authEndpoint = await discoverAuthorizationEndpoint(oidc.issuer);
+    if (authEndpoint) {
+      const url = new URL(authEndpoint);
+      url.searchParams.set('response_type', 'code');
+      url.searchParams.set('client_id', oidc.clientId);
+      url.searchParams.set('redirect_uri', oidc.redirectUri);
+      url.searchParams.set('scope', 'openid profile email');
+      url.searchParams.set('state', signedState);
+      authorizationUrl = url.toString();
+    }
   }
 
   return c.json({ signedState, authorizationUrl }, 200);
diff --git a/apps/api/tests/auth/localAuthMiddleware.test.ts b/apps/api/tests/auth/localAuthMiddleware.test.ts
index 4dc9590..6bba8ab 100644
--- a/apps/api/tests/auth/localAuthMiddleware.test.ts
+++ b/apps/api/tests/auth/localAuthMiddleware.test.ts
@@ -155,6 +155,36 @@ describe('localAuthMiddleware', () => {
     expect(u.color).toBe('#FF5733');
   });
 
+  it('Test 1c (BL-04): local user with null DB oidc fields → context oidcIss/oidcSub are NULL (no fabricated sentinels)', async () => {
+    mockVerifyResult = 9;
+    mockDbSelectResult.push({
+      id: 9,
+      oidcIss: null, // local user — no OIDC identity bound
+      oidcSub: null,
+      displayName: 'Local Member',
+      color: '#22AA88',
+    });
+
+    const localAuthMiddleware = await getMiddleware();
+    const app = new Hono();
+    let capturedUser: unknown;
+
+    app.use('/api/*', localAuthMiddleware());
+    app.get('/api/test', (c) => {
+      capturedUser = c.get('user');
+      return c.json({ ok: true });
+    });
+
+    const res = await app.request('/api/test');
+    expect(res.status).toBe(200);
+    const u = capturedUser as { id: number; oidcIss: string | null; oidcSub: string | null };
+    expect(u.id).toBe(9);
+    // BL-04: must be null — NOT 'local' / String(id) sentinels that share the
+    // uniq_oidc_identity domain with real OIDC identities.
+    expect(u.oidcIss).toBeNull();
+    expect(u.oidcSub).toBeNull();
+  });
+
   it('Test 2: no cookie → pure passthrough; c.get("user") remains unset (Pitfall-1 guard)', async () => {
     mockVerifyResult = null; // No cookie / invalid
 
diff --git a/apps/api/tests/auth/localCredentials.test.ts b/apps/api/tests/auth/localCredentials.test.ts
index 5bc5433..55b03e8 100644
--- a/apps/api/tests/auth/localCredentials.test.ts
+++ b/apps/api/tests/auth/localCredentials.test.ts
@@ -4,6 +4,9 @@
  * Uses node:crypto scrypt under the hood; no external dependencies.
  * All tests run without MariaDB or any external service.
  *
+ * WR-03: hashPassword / verifyPassword are now async (promisify(scrypt), threadpool) —
+ * all assertions await them.
+ *
  * Test suite (TDD RED → GREEN — Plan 19-01 Task 1):
  *   Test 1: correct password verifies true
  *   Test 2: wrong password verifies false
@@ -13,36 +16,72 @@
  */
 
 import { describe, it, expect } from 'vitest';
+import { scryptSync, randomBytes } from 'node:crypto';
 import { hashPassword, verifyPassword } from '../../src/auth/localCredentials.js';
 
 describe('hashPassword / verifyPassword', () => {
-  it('Test 1: verifyPassword(hashPassword(pw), pw) === true (round-trip)', () => {
-    const encoded = hashPassword('hunter2');
-    const result = verifyPassword(encoded, 'hunter2');
+  it('Test 1: verifyPassword(hashPassword(pw), pw) === true (round-trip)', async () => {
+    const encoded = await hashPassword('hunter2');
+    const result = await verifyPassword(encoded, 'hunter2');
     expect(result).toBe(true);
   });
 
-  it('Test 2: verifyPassword(hashPassword(pw), wrong) === false', () => {
-    const encoded = hashPassword('hunter2');
-    const result = verifyPassword(encoded, 'wrong-password');
+  it('Test 2: verifyPassword(hashPassword(pw), wrong) === false', async () => {
+    const encoded = await hashPassword('hunter2');
+    const result = await verifyPassword(encoded, 'wrong-password');
     expect(result).toBe(false);
   });
 
-  it('Test 3: two hashPassword calls on same input produce different encoded strings (unique salt)', () => {
-    const encoded1 = hashPassword('x');
-    const encoded2 = hashPassword('x');
+  it('Test 3: two hashPassword calls on same input produce different encoded strings (unique salt)', async () => {
+    const encoded1 = await hashPassword('x');
+    const encoded2 = await hashPassword('x');
     expect(encoded1).not.toBe(encoded2);
   });
 
-  it('Test 4: verifyPassword returns false (never throws) on a malformed stored hash', () => {
-    expect(() => verifyPassword('not-a-valid-hash', 'x')).not.toThrow();
-    expect(verifyPassword('not-a-valid-hash', 'x')).toBe(false);
-    expect(verifyPassword('', 'x')).toBe(false);
-    expect(verifyPassword('scrypt$bad$data', 'x')).toBe(false);
+  it('Test 4: verifyPassword returns false (never throws) on a malformed stored hash', async () => {
+    await expect(verifyPassword('not-a-valid-hash', 'x')).resolves.toBe(false);
+    await expect(verifyPassword('', 'x')).resolves.toBe(false);
+    await expect(verifyPassword('scrypt$bad$data', 'x')).resolves.toBe(false);
   });
 
-  it('Test 5: encoded string has scrypt$N$r$p$salt$hash shape (6 $-delimited segments)', () => {
-    const encoded = hashPassword('testpassword');
+  it('Test 6 (IN-02): a hash produced by the INLINED scrypt parameters round-trips against the canonical verifyPassword', async () => {
+    // IN-02: the PHC scrypt hash is copy-pasted in three places — the canonical module
+    // (src/auth/localCredentials.ts), the break-glass CLI (scripts/reset-admin.ts), and the
+    // CI seed step (.gitea/workflows/ci.yml). If the parameters ever drift, those inlined
+    // copies would produce hashes the canonical verifyPassword cannot validate, silently
+    // breaking login for seeded/reset accounts. This test pins the inlined parameter set:
+    // if anyone changes N/r/p/KEY_LEN in the canonical module without updating the inlined
+    // copies (or vice versa), this round-trip fails loudly in CI.
+    //
+    // These constants MUST match scripts/reset-admin.ts and .gitea/workflows/ci.yml exactly.
+    const INLINE_N = 16384;
+    const INLINE_R = 8;
+    const INLINE_P = 1;
+    const INLINE_KEY_LEN = 32;
+
+    const password = 'inline-roundtrip-pw';
+    const salt = randomBytes(16);
+    const hash = scryptSync(password, salt, INLINE_KEY_LEN, {
+      N: INLINE_N,
+      r: INLINE_R,
+      p: INLINE_P,
+    });
+    const inlineEncoded = [
+      'scrypt',
+      INLINE_N,
+      INLINE_R,
+      INLINE_P,
+      salt.toString('base64url'),
+      hash.toString('base64url'),
+    ].join('$');
+
+    // The canonical verifyPassword must validate a hash produced by the inlined params.
+    expect(await verifyPassword(inlineEncoded, password)).toBe(true);
+    expect(await verifyPassword(inlineEncoded, 'wrong')).toBe(false);
+  });
+
+  it('Test 5: encoded string has scrypt$N$r$p$salt$hash shape (6 $-delimited segments)', async () => {
+    const encoded = await hashPassword('testpassword');
     const segments = encoded.split('$');
     expect(segments).toHaveLength(6);
     expect(segments[0]).toBe('scrypt');
diff --git a/apps/api/tests/routes/admin.test.ts b/apps/api/tests/routes/admin.test.ts
index c525fe4..0a12737 100644
--- a/apps/api/tests/routes/admin.test.ts
+++ b/apps/api/tests/routes/admin.test.ts
@@ -483,6 +483,19 @@ describe('PUT /api/admin/calendars/:id/shared', () => {
       .limit(1);
     expect(rowA.isShared).toBe(true);
   });
+
+  it('WR-07: rejects a calendar id with trailing garbage (e.g. "1abc") with 400', async () => {
+    const adminId = await seedUser('admin-shared-badid', true);
+    currentDevUserId = adminId;
+    const app = await getApp();
+
+    // parseInt('1abc', 10) === 1 would have silently accepted this; the strict
+    // Number.isInteger parse must reject it as a malformed id.
+    const res = await app.fetch(jsonRequest('PUT', '/api/admin/calendars/1abc/shared'));
+    expect(res.status).toBe(400);
+    const body = (await res.json()) as { error: string };
+    expect(body.error).toBe('Invalid calendar id');
+  });
 });
 
 // ===========================================================================
@@ -890,7 +903,7 @@ describe('POST /api/admin/members', () => {
       .where(eq(localCredentials.userId, body.id))
       .limit(1);
     expect(credRow).toBeDefined();
-    expect(verifyPassword(credRow.passwordHash, initialPassword)).toBe(true);
+    expect(await verifyPassword(credRow.passwordHash, initialPassword)).toBe(true);
   });
 
   it('Test 2: duplicate username returns 409 — transaction rolls back (no orphaned users row)', async () => {
@@ -967,8 +980,8 @@ describe('POST /api/admin/members', () => {
       .where(eq(localCredentials.userId, newMemberId))
       .limit(1);
     expect(credRow).toBeDefined();
-    expect(verifyPassword(credRow.passwordHash, newPassword)).toBe(true);
-    expect(verifyPassword(credRow.passwordHash, 'old-password-123')).toBe(false);
+    expect(await verifyPassword(credRow.passwordHash, newPassword)).toBe(true);
+    expect(await verifyPassword(credRow.passwordHash, 'old-password-123')).toBe(false);
   });
 
   it('Test 4: non-admin gets 403 on POST /members and POST /members/:id/password', async () => {
@@ -1023,4 +1036,29 @@ describe('POST /api/admin/members', () => {
     expect(adminRow).toBeDefined();
     expect(adminRow!.hasLocalCredential).toBe(false);
   });
+
+  it('WR-05 (no-echo): malformed create-member body never echoes the submitted password or Zod received field', async () => {
+    const adminId = await seedUser('admin-create-noecho', true);
+    currentDevUserId = adminId;
+    const app = await getApp();
+
+    // initialPassword too short (< 8) → Zod rejects. The noEchoHook must return only
+    // { error: 'Invalid request' } and NEVER leak the submitted password or Zod's
+    // issues[].received field (T-19-06 / the T-19-14 leak this guards against).
+    const submittedPassword = 'shortpw-secret';
+    const res = await app.fetch(
+      jsonRequest('POST', '/api/admin/members', {
+        displayName: 'No Echo',
+        username: `noecho-${randomUUID()}`,
+        initialPassword: submittedPassword.slice(0, 3), // 3 chars — fails min(8)
+      }),
+    );
+    expect(res.status).toBe(400);
+    const bodyText = await res.text();
+    expect(bodyText).not.toContain('received');
+    expect(bodyText).not.toContain('issues');
+    expect(bodyText).not.toContain(submittedPassword.slice(0, 3));
+    const parsed = JSON.parse(bodyText) as { error: string };
+    expect(parsed.error).toBe('Invalid request');
+  });
 });
diff --git a/apps/api/tests/routes/localAuth.test.ts b/apps/api/tests/routes/localAuth.test.ts
index ee4cbb3..6f511d3 100644
--- a/apps/api/tests/routes/localAuth.test.ts
+++ b/apps/api/tests/routes/localAuth.test.ts
@@ -5,8 +5,9 @@
  *   Test 1: valid username+password → 200 { ok:true } + Set-Cookie for local-session
  *   Test 2: wrong password → 401 { error: 'Invalid credentials' }
  *   Test 3: unknown username → 401 with SAME body as Test 2 (no enumeration / no field discrimination)
- *   Test 4: 5 consecutive failures from one IP → 6th returns 429
+ *   Test 4: 5 consecutive failures for one username → 6th returns 429
  *   Test 5: 10 failures → 423 (lockedOut); a cleared map resets the counter
+ *   Test 5b (CR-04): a 423 lockout auto-expires after LOCKOUT_TTL_MS (no admin reset needed)
  *   Test 6: POST /api/auth/local/logout clears the local-session cookie (expired Set-Cookie)
  *   Test 6b: GET /api/auth/local/logout (alias) also clears the local-session cookie
  *   Test 7 (no-echo): malformed body (missing password) → 400 { error: 'Invalid request' };
@@ -163,7 +164,7 @@ async function getLocalCredentials() {
 describe('POST /api/auth/local/login', () => {
   it('Test 1: valid username+password → 200 { ok:true } and issueLocalSessionCookie called', async () => {
     const { hashPassword } = await getLocalCredentials();
-    const hash = hashPassword('correcthorse');
+    const hash = await hashPassword('correcthorse');
     mockCredRow = { userId: 5, passwordHash: hash };
 
     const app = await getApp();
@@ -178,7 +179,7 @@ describe('POST /api/auth/local/login', () => {
 
   it('Test 2: wrong password → 401 { error: "Invalid credentials" }', async () => {
     const { hashPassword } = await getLocalCredentials();
-    const hash = hashPassword('correcthorse');
+    const hash = await hashPassword('correcthorse');
     mockCredRow = { userId: 5, passwordHash: hash };
 
     const app = await getApp();
@@ -246,8 +247,9 @@ describe('POST /api/auth/local/login', () => {
     expect(body.error).toBe('Account locked');
 
     // Clear the map (simulates admin reset) → counter gone → next attempt is 401 again (not locked)
+    // CR-04: the limiter is keyed on the USERNAME ('alice'), not the IP.
     const { loginAttempts } = await import('../../src/routes/localAuth.js');
-    loginAttempts.delete('10.0.0.2');
+    loginAttempts.delete('alice');
 
     const resAfterReset = await app.fetch(
       makeLoginRequest({ username: 'alice', password: 'wrong' }, '10.0.0.2')
@@ -255,6 +257,36 @@ describe('POST /api/auth/local/login', () => {
     expect(resAfterReset.status).toBe(401);
   });
 
+  it('Test 5b (CR-04): a 423 lockout auto-expires after the TTL — no admin reset needed', async () => {
+    mockCredRow = undefined;
+
+    const app = await getApp();
+
+    // 10 failures → lockout for username 'bob'
+    for (let i = 0; i < 10; i++) {
+      await app.fetch(makeLoginRequest({ username: 'bob', password: 'wrong' }, '10.0.0.3'));
+    }
+
+    // Confirm locked (423)
+    const resLocked = await app.fetch(
+      makeLoginRequest({ username: 'bob', password: 'wrong' }, '10.0.0.3'),
+    );
+    expect(resLocked.status).toBe(423);
+
+    // Simulate the TTL elapsing by back-dating lockedAt well past LOCKOUT_TTL_MS (15 min).
+    const { loginAttempts } = await import('../../src/routes/localAuth.js');
+    const entry = loginAttempts.get('bob');
+    expect(entry?.lockedOut).toBe(true);
+    if (entry) entry.lockedAt = Date.now() - 16 * 60 * 1000;
+
+    // Next attempt: the lockout has expired → handler drops the entry and processes the
+    // login normally, so a wrong password is a fresh 401 (not a 423). CR-04: self-healing.
+    const resAfterTtl = await app.fetch(
+      makeLoginRequest({ username: 'bob', password: 'wrong' }, '10.0.0.3'),
+    );
+    expect(resAfterTtl.status).toBe(401);
+  });
+
   it('Test 7 (no-echo): malformed body (missing password) → 400 { error: "Invalid request" }; body has no echoed value or Zod received field', async () => {
     const app = await getApp();
     // Body with username but missing password (Zod will reject)
diff --git a/apps/api/tests/routes/me.test.ts b/apps/api/tests/routes/me.test.ts
index 7eb6e30..6f50480 100644
--- a/apps/api/tests/routes/me.test.ts
+++ b/apps/api/tests/routes/me.test.ts
@@ -274,7 +274,7 @@ describe('POST /api/me/password — self-change password (AUTH-LOCAL-09)', () =>
 
     const oldPassword = 'old-password-correct-123';
     const newPassword = 'new-password-secure-456';
-    const storedHash = hashPassword(oldPassword);
+    const storedHash = await hashPassword(oldPassword);
     let updatedHash: string | null = null;
 
     // Mock sequence: resolveUserId (devBypass sets user), then:
@@ -326,15 +326,15 @@ describe('POST /api/me/password — self-change password (AUTH-LOCAL-09)', () =>
     // The updatedHash must verify the new password
     expect(updatedHash).not.toBeNull();
     const { verifyPassword } = await import('../../src/auth/localCredentials.js');
-    expect(verifyPassword(updatedHash!, newPassword)).toBe(true);
-    expect(verifyPassword(updatedHash!, oldPassword)).toBe(false);
+    expect(await verifyPassword(updatedHash!, newPassword)).toBe(true);
+    expect(await verifyPassword(updatedHash!, oldPassword)).toBe(false);
   });
 
-  it('Test 2: wrong currentPassword → 401 and update is NOT called', async () => {
+  it('Test 2: wrong currentPassword → 403 and update is NOT called', async () => {
     const { db } = await import('../../src/db/client.js');
 
     const realPassword = 'real-password-correct-789';
-    const storedHash = hashPassword(realPassword);
+    const storedHash = await hashPassword(realPassword);
     let updateWasCalled = false;
 
     let callCount = 0;
@@ -374,7 +374,9 @@ describe('POST /api/me/password — self-change password (AUTH-LOCAL-09)', () =>
       body: JSON.stringify({ currentPassword: 'WRONG-password', newPassword: 'new-pass-12345678' }),
     });
 
-    expect(res.status).toBe(401);
+    // CR-03: wrong current password returns 403 (in-app authz failure), NOT 401.
+    // A 401 would be interpreted by the PWA as session expiry and log the user out.
+    expect(res.status).toBe(403);
     const body = (await res.json()) as { error: string };
     expect(body.error).toBe('Current password incorrect');
     // Update must NOT have been called
@@ -401,6 +403,27 @@ describe('POST /api/me/password — self-change password (AUTH-LOCAL-09)', () =>
 
     expect(res.status).toBe(404);
   });
+
+  it('Test 4 (WR-05 no-echo): malformed body never echoes the submitted password or Zod received field', async () => {
+    // newPassword too short (< 8) → Zod rejects via meNoEchoHook. The response must be
+    // ONLY { error: 'Invalid request' } and must NOT leak the submitted password or the
+    // Zod issues[].received field (T-19-06).
+    const { app } = await import('../../src/index.js');
+    const submitted = 'my-secret-current-pw';
+    const res = await app.request('/api/me/password', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ currentPassword: submitted, newPassword: 'short' }),
+    });
+
+    expect(res.status).toBe(400);
+    const bodyText = await res.text();
+    expect(bodyText).not.toContain(submitted);
+    expect(bodyText).not.toContain('received');
+    expect(bodyText).not.toContain('issues');
+    const parsed = JSON.parse(bodyText) as { error: string };
+    expect(parsed.error).toBe('Invalid request');
+  });
 });
 
 // ---------------------------------------------------------------------------
diff --git a/apps/pwa/src/api/client.ts b/apps/pwa/src/api/client.ts
index 7067342..7bd52a8 100644
--- a/apps/pwa/src/api/client.ts
+++ b/apps/pwa/src/api/client.ts
@@ -141,9 +141,14 @@ export async function fetchLocalLogout(): Promise<void> {
  * Requires the user's current password and a new password (min 8 chars).
  *
  * Status codes:
- *   401 → wrong current password (throws Error with code 'wrong-current')
- *   422 → validation failure (throws Error with code 'validation')
- *   other non-ok → generic error
+ *   403 → wrong current password (throws Error('wrong-current')) — NOT a session expiry
+ *   401 / opaqueredirect → genuine session expiry (throws SessionExpiredError)
+ *   other non-ok → generic error (throws Error('server'))
+ *
+ * CR-03: the server returns 403 (not 401) for an incorrect current password so this
+ * client can distinguish an in-app authorization failure from a real session expiry.
+ * Treating that case as 401 would route it to the global MutationCache session-expiry
+ * handler and forcibly log the user out for a simple mistyped password.
  */
 export async function fetchChangePassword(body: {
   currentPassword: string;
@@ -157,6 +162,8 @@ export async function fetchChangePassword(body: {
     body: JSON.stringify(body),
   });
 
+  // 403 → wrong current password (in-app). Check BEFORE the 401 session-expiry branch.
+  if (res.status === 403) throw new Error('wrong-current');
   if (res.type === 'opaqueredirect' || res.status === 401) throw new SessionExpiredError();
   if (!res.ok) {
     const detail = (await res.json().catch(() => ({}))) as { code?: string };
@@ -168,10 +175,14 @@ export async function fetchChangePassword(body: {
  * POST /api/admin/members — create a new local member account (Phase 19, Surface 11A).
  * Admin-only; server enforces requireAdmin.
  *
+ * Request contract: the server's createMemberSchema requires
+ *   { displayName, username, initialPassword }
+ * (see apps/api/src/routes/admin.ts). The caller-facing `password` field is mapped to
+ * `initialPassword` here so the request validates server-side.
+ *
  * Status codes:
- *   409 → username already taken
- *   422 → validation failure (short password / mismatch)
- *   other non-ok → generic error
+ *   409 → username already taken (throws Error with message 'conflict')
+ *   other non-ok → generic error (throws Error('server'))
  */
 export async function fetchCreateMember(body: {
   displayName: string;
@@ -183,10 +194,19 @@ export async function fetchCreateMember(body: {
     headers: { 'Content-Type': 'application/json' },
     credentials: 'include',
     redirect: 'manual',
-    body: JSON.stringify(body),
+    // CR-02: the server expects `initialPassword`, not `password`. Send the field it
+    // validates against — otherwise Zod rejects every create with a generic 400.
+    body: JSON.stringify({
+      displayName: body.displayName,
+      username: body.username,
+      initialPassword: body.password,
+    }),
   });
 
   if (res.type === 'opaqueredirect' || res.status === 401) throw new SessionExpiredError();
+  // 409 → username conflict. The server returns { error: 'Username already in use' } (no
+  // `code` field), so map the status to the 'conflict' sentinel the AdminPage handler expects.
+  if (res.status === 409) throw new Error('conflict');
   if (!res.ok) {
     const detail = (await res.json().catch(() => ({}))) as { code?: string };
     throw new Error(detail.code ?? 'server');
@@ -219,11 +239,15 @@ export async function fetchAdminResetPassword(
 /**
  * POST /api/me/link-oidc — initiate the OIDC-link flow for the current local user (Surface 13).
  *
- * The server returns a redirect URL to begin the OIDC authorization-code flow with a
- * state parameter encoding the linkUserId claim. The caller should follow the redirect
- * via top-level navigation (window.location.href = result.redirectUrl).
+ * The server returns the OIDC authorization endpoint URL (with a signed `state` parameter
+ * encoding the linkUserId claim) to begin the authorization-code flow. The caller should
+ * follow it via top-level navigation (window.location.href = authorizationUrl) when present.
+ *
+ * authorizationUrl is null when OIDC is not configured in env (the server cannot build the
+ * URL); callers MUST handle that case and surface an error instead of navigating to null.
+ * The server contract is { signedState, authorizationUrl } (see apps/api/src/routes/me.ts).
  */
-export async function fetchLinkOidc(): Promise<{ redirectUrl: string }> {
+export async function fetchLinkOidc(): Promise<{ authorizationUrl: string | null }> {
   const res = await fetch('/api/me/link-oidc', {
     method: 'POST',
     credentials: 'include',
@@ -234,7 +258,7 @@ export async function fetchLinkOidc(): Promise<{ redirectUrl: string }> {
   if (!res.ok) {
     throw new Error(`fetchLinkOidc failed: ${res.status}`);
   }
-  return res.json() as Promise<{ redirectUrl: string }>;
+  return res.json() as Promise<{ signedState: string; authorizationUrl: string | null }>;
 }
 
 // ── /api/me ────────────────────────────────────────────────────────────────
diff --git a/apps/pwa/src/components/SettingsSheet.tsx b/apps/pwa/src/components/SettingsSheet.tsx
index 287af72..59f5b1a 100644
--- a/apps/pwa/src/components/SettingsSheet.tsx
+++ b/apps/pwa/src/components/SettingsSheet.tsx
@@ -859,9 +859,15 @@ function LinkOidcSheet({ isOpen, onClose }: LinkOidcSheetProps) {
   const linkMutation = useMutation({
     mutationFn: fetchLinkOidc,
     onSuccess: (data) => {
-      // Close the sheet and initiate OIDC link flow
+      // authorizationUrl is null when OIDC is not configured in env (server could not
+      // build the URL). Do NOT navigate to null — surface an error and keep the sheet open.
+      if (!data.authorizationUrl) {
+        setError('Something went wrong. Please try again.');
+        return;
+      }
+      // Close the sheet and initiate the OIDC link flow via top-level navigation.
       onClose();
-      window.location.href = data.redirectUrl;
+      window.location.href = data.authorizationUrl;
     },
     onError: () => {
       setError('Something went wrong. Please try again.');
diff --git a/apps/pwa/src/routes/LoginPage.tsx b/apps/pwa/src/routes/LoginPage.tsx
index 22f3807..921178e 100644
--- a/apps/pwa/src/routes/LoginPage.tsx
+++ b/apps/pwa/src/routes/LoginPage.tsx
@@ -332,7 +332,8 @@ export function LoginPage({ authMode }: LoginPageProps) {
                   }}
                 >
                   <AlertCircle size={16} aria-hidden="true" style={{ flexShrink: 0 }} />
-                  This account is temporarily locked. Contact your admin to reset access.
+                  Too many failed attempts for this account. Try again in about 15 minutes, or
+                  contact your admin to reset access.
                 </div>
               )}