diff --git a/src/main/browser/browser-session-registry.persistence.test.ts b/src/main/browser/browser-session-registry.persistence.test.ts
index 697e9448d..346d08132 100644
--- a/src/main/browser/browser-session-registry.persistence.test.ts
+++ b/src/main/browser/browser-session-registry.persistence.test.ts
@@ -243,4 +243,37 @@ describe('BrowserSessionRegistry persistence', () => {
     expect(written.pendingCookieImports).toEqual({ [importedPartition]: '/staged/imported' })
     expect(written.pendingCookieDbPath).toBeNull()
   })
+
+  it('ignores pending cookie imports for invalid persisted profile partitions', async () => {
+    const invalidPartition = 'persist:../../outside'
+    const fsState = createFsState()
+    seedMeta(fsState, {
+      defaultSource: null,
+      userAgent: null,
+      userAgentByPartition: {},
+      pendingCookieDbPath: null,
+      pendingCookieImports: {
+        [invalidPartition]: '/staged/evil'
+      },
+      profiles: [
+        {
+          id: 'profile-1',
+          scope: 'imported',
+          partition: invalidPartition,
+          label: 'Invalid',
+          source: null
+        }
+      ]
+    })
+    fsState.present.add('/staged/evil')
+
+    installModuleMocks(fsState)
+    const { browserSessionRegistry } = await import('./browser-session-registry')
+
+    browserSessionRegistry.applyPendingCookieImport()
+
+    const written = JSON.parse(fsState.files.get(META_PATH) ?? '{}')
+    expect(written.pendingCookieImports).toEqual({})
+    expect(fsState.present.has('/outside/Cookies')).toBe(false)
+  })
 })
diff --git a/src/main/browser/browser-session-registry.ts b/src/main/browser/browser-session-registry.ts
index 43bc0fb67..857c5dc3c 100644
--- a/src/main/browser/browser-session-registry.ts
+++ b/src/main/browser/browser-session-registry.ts
@@ -192,10 +192,14 @@ class BrowserSessionRegistry {
       if (pendingEntries.length === 0) {
         return
       }
-      const knownPartitions = new Set([
-        ORCA_BROWSER_PARTITION,
-        ...meta.profiles.map((p) => p.partition)
-      ])
+      // Why: replay writes to partition-derived file paths, so corrupted
+      // metadata must pass the same validation as the webview allowlist.
+      const knownPartitions = new Set([ORCA_BROWSER_PARTITION])
+      for (const profile of meta.profiles) {
+        if (BrowserSessionRegistry.isValidPersistedProfile(profile)) {
+          knownPartitions.add(profile.partition)
+        }
+      }
       const remainingEntries = { ...meta.pendingCookieImports }
 
       for (const [partition, stagedPath] of pendingEntries) {
@@ -426,17 +430,24 @@ class BrowserSessionRegistry {
   // registering anything.
   private static readonly PARTITION_RE = /^persist:orca-browser-session-[\da-f-]{36}$/
 
+  private static isValidPersistedProfile(profile: unknown): profile is BrowserSessionProfile {
+    if (!profile || typeof profile !== 'object') {
+      return false
+    }
+    const candidate = profile as Partial<BrowserSessionProfile>
+    return (
+      candidate.id !== 'default' &&
+      candidate.scope !== 'default' &&
+      typeof candidate.id === 'string' &&
+      typeof candidate.partition === 'string' &&
+      typeof candidate.label === 'string' &&
+      BrowserSessionRegistry.PARTITION_RE.test(candidate.partition)
+    )
+  }
+
   hydrateFromPersisted(profiles: BrowserSessionProfile[]): void {
     for (const profile of profiles) {
-      if (profile.id === 'default' || profile.scope === 'default') {
-        continue
-      }
-      if (
-        typeof profile.id !== 'string' ||
-        typeof profile.partition !== 'string' ||
-        typeof profile.label !== 'string' ||
-        !BrowserSessionRegistry.PARTITION_RE.test(profile.partition)
-      ) {
+      if (!BrowserSessionRegistry.isValidPersistedProfile(profile)) {
         continue
       }
       this.profiles.set(profile.id, profile)