Turbo Frame responses can restore stale session cookies
Date: 2026-01
Affected: npm/@hotwired/turbo
Attack vector: other
Category: vulnerability-disclosure
Severity: Low
CVE: CVE-2025-66803
CWE: CWE-362
CWE-367
CWE-613

### Summary A race condition in Turbo Frames allows delayed HTTP responses to restore stale session cookies after session-modifying operations. ### Details Browsers automatically process Set-Cookie headers from HTTP responses. When a Turbo Frame request is in-flight during a session-modifying action (such as logout), the delayed response may include a Set-Cookie header reflecting the session state at request time. This can result in stale session cookies being restored after the session was intentionally modified or invalidated. This condition can occur naturally on slow networks. An active network attacker capable of delaying responses could potentially exploit this to restore previous session state. ### Impact Applications using Turbo Frames with cookie-based session storage may experience: - Session state reversion after logout - Unintended restoration of previous authentication state The impact is limited to applications using client-side cookie storage for sessions. Applications using server-side session stores (Redis, database, etc.) are not meaningfully affected, as the server-side session state remains authoritative. ### Patches Upgrade to Turbo 8.0.21 or later. The fix cancels in-flight Turbo Frame requests when: - The frame element is disconnected from the DOM - The frame's disabled attribute is set - The frame's src attribute is cleared ### Workarounds - Use server-side session storage instead of a cookie store like Rails's cookie store


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