Answer in brief
CVE-2026-126076 records a Medium severity (CVSS 4.2) vulnerability in Action Pack: Possible restoration of destroyed sessions in Action Dispatch CacheStore. The current sources do not mark it as known exploited. The current feed maps rails/rails (generic), actionpack (rubygems), actionpack (rubygems). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 4.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps rails/rails (generic), actionpack (rubygems), actionpack (rubygems). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| rails/railsgeneric | >=8.1 <8.1.4.1 || <8.0.5.2 | 8.0.5.2, 8.1.4.1 |
| actionpackrubygems | >=8.1.0.beta1,<8.1.4.1 | 8.1.4.1 |
| actionpackrubygems | <8.0.5.2 | 8.0.5.2 |
Published upstream
Nov 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 10, 2026
Action Pack is a framework for handling and responding to web requests. Prior to 8.1.4.1 and 8.0.5.2, 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 reset_session 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.session_store :cache_store 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. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.
Quoted source text, attributed separately from HOL analysis.