Action Pack: Possible restoration of destroyed sessions in Action Dispatch CacheStore
CVE-2026-126076
Impact ActionDispatch::Session::CacheStore writes a session back to the cache at the end of each request that loaded it, without checking that the session's cache entry still exists. When a concurrent request destroys the session, through resetsession on logout or by deleting its cache entry on the server, a request that loaded the session earlier and finishes later restores it under its original session ID. Logout and server-side revocation could therefore fail to end a session, and an attacker who holds a stolen session cookie could keep that session valid across the victim's logout. Applications that use config.sessionstore :cachestore are affected, with any cache backend. ActionDispatch::Session::CookieStore is not affected, nor is ActionDispatch::Session::MemCacheStore with Dalli 4.0.0 or later, whose session store does not write back a session that was deleted. Details The fixed releases record which session a request loaded and skip the write when that session's cache entry no longer exists. Changes that such a request makes to the destroyed session are discarded, and Rack logs a warning that the session could not be saved. Each request that writes back a session it loaded…
Assessment
- CVSS
- 4.2 (v3.1)
- Severity
- Medium
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 10 November 2026
- Last updated
- 10 November 2026
- Affected
- actionpack
- Weakness
- CWE-613
CVSS vectorCVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
At the source
References
- https://github.com/rails/rails/security/advisories/GHSA-2586-8ghr-69fj
- https://github.com/rails/rails/commit/5bb5ec66ed8faaf590ffe1222d7a5eb6e9d050f5
- https://github.com/rails/rails/commit/d479192cf88a8b30a335a8bc25188a2d8e0f8d9f
- https://github.com/rails/rails/releases/tag/v8.0.5.2
- https://github.com/rails/rails/releases/tag/v8.1.4.1
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/GHSA-2586-8ghr-69fj.yml
- https://github.com/advisories/GHSA-2586-8ghr-69fj
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