@@ -0,0 +1,22 @@
+---
+'@objectstack/core': patch
+---
+
+fix(core)!: `resolveLocalizationContext`'s direct `sys_setting` fallback reads the caller's organization's rows only, never another organization's row or a row with no organization outside a lean embedding
+
+Clause-②: no (narrowing)
+Metadata-protocol: none
+
+<!-- adr-0087: not-required (no-migration-prescription) Which stored `sys_setting` row the localization fallback takes changes. No key of any metadata schema is removed, renamed or re-shaped, so `objectstack migrate meta` has nothing to rewrite and no tombstone is needed. No export, type, error code or route is removed or renamed: `resolveLocalizationContext` keeps its signature. The remedy for the rows this stops reading is the existing organization-ownership ceremony, stated below. The other categories are closed on facts: the package publishes (not unpublished); no ADR-0087 id covers this read (not registered or already-registered); and nothing exported is removed or narrowed (not runtime-interface-only, type-surface-only or runtime-export-retired). -->
+
+**BREAKING** read narrowing (ADR-0131 D8 "no layer has a NULL arm"). It changes which stored row a localization read takes when the settings service cannot answer, not what a metadata author can write, so it ships as `patch` with this banner.
+
+- FROM: when the settings service was absent or threw (a namespace not yet bound, a failed organization or posture read), `resolveLocalizationContext` read `sys_setting` tenant rows for `timezone` / `locale` / `currency` with no organization filter and took the first row per key. A signed-in user of one organization could be answered with another organization's timezone, locale or currency, or with a row written with no organization, and the success cache could hold that answer.
+- TO: the fallback reads with the reach the settings service reads with:
+  - A caller that names an organization reads that organization's rows, under every posture.
+  - A caller that names none reads the one organization ADR-0131 D9 derives under `single`. Behind a wall (`group` / `isolated`, the requested posture), at zero or several organizations, or when the organization read fails, it reads nothing and the built-ins `UTC` / `en-US` answer.
+  - A composition that registers no `sys_organization` (a lean embedding) reads the rows written with no organization, the only rows it can hold.
+
+**Who is affected.** Only a deployment whose settings service fails a localization read, and only for an organization with no tenant localization row of its own, or a store holding organization-less tenant localization rows. A healthy settings service never reaches this read.
+
+**The remedy.** Run `os migrate organization-ownership --out PLAN`, review the reported `sys_setting` rows, and save each localization value again from inside the organization it belongs to (Setup → Localization, or `PUT /api/settings/localization` with that organization active).
@@ -219,9 +219,9 @@ describe('resolveLocalizationContext — batched fallback read (#2409)', () => {
   it('reads sys_setting once (all three keys) when no settings service is wired', async () => {
     const ql = makeCountingQl({
       sys_setting: [
-        { namespace: 'localization', key: 'timezone', scope: 'tenant', value: 'Asia/Tokyo' },
-        { namespace: 'localization', key: 'locale', scope: 'tenant', value: 'ja-JP' },
-        { namespace: 'localization', key: 'currency', scope: 'tenant', value: 'JPY' },
+        { namespace: 'localization', key: 'timezone', scope: 'tenant', organization_id: 'o1', value: 'Asia/Tokyo' },
+        { namespace: 'localization', key: 'locale', scope: 'tenant', organization_id: 'o1', value: 'ja-JP' },
+        { namespace: 'localization', key: 'currency', scope: 'tenant', organization_id: 'o1', value: 'JPY' },
       ],
     });
     const loc = await resolveLocalizationContext({ ql, tenantId: 'o1' });
@@ -283,7 +283,7 @@ describe('resolveLocalizationContext — batched fallback read (#2409)', () => {
     };
     const ql = makeCountingQl({
       sys_setting: [
-        { namespace: 'localization', key: 'timezone', scope: 'tenant', value: 'Europe/Paris' },
+        { namespace: 'localization', key: 'timezone', scope: 'tenant', organization_id: 'o1', value: 'Europe/Paris' },
       ],
     });
     const loc = await resolveLocalizationContext({ ql, settings, tenantId: 'o1' });
@@ -505,7 +505,7 @@ describe('resolveLocalizationContext — failure-only cross-request cache (#1022
   // the same staleness property through the invalidation instead of through the
   // absence of a cache.
   it('without an engine write-epoch seam, a successful read is never cached: a value change between two calls is visible on the very next call', async () => {
-    const rows = [{ namespace: 'localization', key: 'timezone', scope: 'tenant', value: 'UTC' }];
+    const rows = [{ namespace: 'localization', key: 'timezone', scope: 'tenant', organization_id: 'o1', value: 'UTC' }];
     const ql = makeCountingQl({ sys_setting: rows });
     const first = await resolveLocalizationContext({ ql, tenantId: 'o1' });
     expect(first.timezone).toBe('UTC');
@@ -523,11 +523,11 @@ describe('resolveLocalizationContext — failure-only cross-request cache (#1022
   // unconfigured tenant must be visible on the very next call, same as the
   // value-change case above. (#11966: same seam-absent arm as that case.)
   it('without a seam, a legitimate empty result is not cached either: the first write for a previously-unconfigured tenant is visible immediately', async () => {
-    const rows: Array<{ namespace: string; key: string; scope: string; value: string }> = [];
+    const rows: Array<{ namespace: string; key: string; scope: string; organization_id: string; value: string }> = [];
     const ql = makeCountingQl({ sys_setting: rows });
     const first = await resolveLocalizationContext({ ql, tenantId: 'o1' });
     expect(first).toEqual({ timezone: 'UTC', locale: 'en-US', currency: undefined });
-    rows.push({ namespace: 'localization', key: 'timezone', scope: 'tenant', value: 'Asia/Tokyo' });
+    rows.push({ namespace: 'localization', key: 'timezone', scope: 'tenant', organization_id: 'o1', value: 'Asia/Tokyo' });
     const second = await resolveLocalizationContext({ ql, tenantId: 'o1' });
     expect(second.timezone).toBe('Asia/Tokyo');
     expect(ql.counts.sys_setting).toBe(2);
@@ -627,7 +627,7 @@ describe('resolveLocalizationContext — only a backend fault populates the memo
   // has nothing to do with the backend.
   it('a settings refusal never freezes a SUCCESSFUL direct read: a row change is visible on the very next call', async () => {
     const settings = makeBindWindowSettings(); // stays unbound → refuses every call
-    const rows = [{ namespace: 'localization', key: 'timezone', scope: 'tenant', value: 'UTC' }];
+    const rows = [{ namespace: 'localization', key: 'timezone', scope: 'tenant', organization_id: 'o1', value: 'UTC' }];
     const ql = makeCountingQl({ sys_setting: rows });
 
     const first = await resolveLocalizationContext({ ql, settings, tenantId: 'o1' });
 
@@ -2386,7 +2386,9 @@ function putLocalizationEntry(ql: object, key: string, entry: LocalizationCacheE
  * Resolve workspace localization defaults (reference `timezone` / `locale` /
  * `currency`). Canonical path is the `localization` SettingsManifest (cascade:
  * platform default → global → tenant); falls back to direct tenant-scoped
- * `sys_setting` rows, then the built-ins `UTC` / `en-US`. Never throws.
+ * `sys_setting` rows of the caller's organization only (ADR-0131 D8 — see
+ * {@link localizationFallbackReach}), then the built-ins `UTC` / `en-US`.
+ * Never throws.
  *
  * The DIRECT `sys_setting` read failing outright (backend fault — table
  * missing, connection refused, etc.) is memoized for
@@ -2461,6 +2463,56 @@ export async function resolveLocalizationContext(input: ResolveLocalizationInput
   return value;
 }
 
+/**
+ * [ADR-0131 D8/D9] Which `sys_setting` tenant rows the direct localization
+ * fallback in {@link resolveLocalizationContextUncached} may draw on — the
+ * reach `SettingsService` reads the same rows with, so the fallback can never
+ * answer what the service it stands in for would refuse:
+ *
+ *  - `own` — one organization's rows: the caller's, under every posture; or,
+ *    for a caller that names none where no wall stands, the one organization
+ *    D9's predicate derives ({@link resolveGuestOrganization}).
+ *  - `no-organization-object` — the composition registers no organization
+ *    object (the lean embedding, kept by ADR-0131's D9 note): the rows written
+ *    with no organization, the only rows it can hold.
+ *  - `unowned` — nothing to read: a caller that names no organization behind a
+ *    wall, where D9 derives none (zero organizations, or several), or where
+ *    the derivation could not be asked (a failed organization read). The
+ *    built-in defaults answer.
+ *
+ * The posture is the REQUESTED one ({@link resolveTenancyPosture}), as the
+ * platform-standing anchor in this file reads it: a deployment that asked for
+ * a wall stays walled here even while running degraded, and the posture costs
+ * no query. This fallback is reached only when the settings service is absent
+ * or has just failed, so it takes no inputs that service would supply.
+ */
+async function localizationFallbackReach(
+  ql: any,
+  tenantId: string | undefined,
+): Promise<
+  | { kind: 'own'; organizationId: string }
+  | { kind: 'no-organization-object' }
+  | { kind: 'unowned' }
+> {
+  if (typeof tenantId === 'string' && tenantId !== '') return { kind: 'own', organizationId: tenantId };
+  try {
+    const decision = await resolveGuestOrganization(ql, resolveTenancyPosture());
+    if (decision.kind === 'derived') return { kind: 'own', organizationId: decision.organizationId };
+    if (decision.kind === 'no-organization-object') return { kind: 'no-organization-object' };
+  } catch {
+    // The organization could not be derived (`AuthzStoreUnavailableError`):
+    // no organization's row is read on a guess. Not the direct read's own
+    // backend fault, so it does not populate the failure memo (#10221).
+  }
+  return { kind: 'unowned' };
+}
+
+/** A `sys_setting` row's organization, with "no organization" spelled one way. */
+function settingRowOrganizationOf(row: any): string | null {
+  const organizationId = row?.organization_id;
+  return typeof organizationId === 'string' && organizationId !== '' ? organizationId : null;
+}
+
 async function resolveLocalizationContextUncached(
   input: ResolveLocalizationInput,
 ): Promise<{ value: LocalizationResult; backendFailed: boolean }> {
@@ -2525,6 +2577,10 @@ async function resolveLocalizationContextUncached(
     // Settings service unavailable → direct read. Still not a backend fault,
     // so it does not populate the memo either (#11877).
   }
+  // [ADR-0131 D8] The organization this read may draw on — the reach the
+  // settings service itself reads with (#25226): never another organization's
+  // row, and a row with no organization only where no organization can exist.
+  const reach = await localizationFallbackReach(ql, tenantId);
   // One read for all three keys instead of a query per key (`$in` on `key`).
   // Inlined (rather than the shared `tryFind`) so a genuine backend fault —
   // as opposed to a legitimate empty result — is visible to the caller above,
@@ -2534,15 +2590,23 @@ async function resolveLocalizationContextUncached(
   // query-options-erasure guard: that cast is a distinct, counted erasure
   // site, not implied by an already-`any` receiver).
   let rows: any[] = [];
-  if (ql && typeof ql.find === 'function') {
+  if (reach.kind !== 'unowned' && ql && typeof ql.find === 'function') {
+    const organization_id = reach.kind === 'own' ? reach.organizationId : null;
     try {
       let result = await ql.find('sys_setting', {
-        where: { namespace: 'localization', key: { $in: ['timezone', 'locale', 'currency'] }, scope: 'tenant' },
+        where: {
+          namespace: 'localization',
+          key: { $in: ['timezone', 'locale', 'currency'] },
+          scope: 'tenant',
+          organization_id,
+        },
         limit: 10,
         context: { isSystem: true },
       });
       if (result && (result as any).value) result = (result as any).value;
-      rows = Array.isArray(result) ? result : [];
+      // The organization is compared HERE too, not trusted to the filter —
+      // the settings service's own rule (`preferredRow`).
+      rows = (Array.isArray(result) ? result : []).filter((r) => settingRowOrganizationOf(r) === organization_id);
     } catch {
       // THE backend fault the failure memo exists for (#10221).
       backendFailed = true;