🛡️ CVE-2025-46336 — rack-session

🟡 CVSS 4.2 — Medium ✅ No Known Exploit CWE-362 NVD
4.2
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Rack session gets restored after deletion

Summary

When using the Rack::Session::Pool middleware, simultaneous rack requests can restore a deleted rack session, which allows the unauthenticated user to occupy that session.

Details

[Rack session middleware](https://github.com/rack/rack-session/blob/v2.1.0/lib/rack/session/abstract/id.rb#L271-L278) prepares the session at the beginning of request, then saves is back to the store with possible changes applied by host rack application. This way the session becomes to be a subject of race conditions in general sense over concurrent rack requests.

Impact

When using the Rack::Session::Pool middleware, and provided the attacker can acquire a session cookie (already a major issue), the session may be restored if the attacker can trigger a long running request (within that same session) adjacent to the user logging out, in order to retain illicit access even after a user has attempted to logout.

Mitigation

  • Update to the latest version of rack-session, or
  • Ensure your application invalidates sessions atomically by marking them as logged out e.g., using a logged_out flag, instead of deleting them, and check this flag on every request to prevent reuse, or
  • Implement a custom session store that tracks session invalidation timestamps and refuses to accept session data if the session was invalidated after the request began.

Related

This code was previously part of rack in Rack < 3, see <https://github.com/rack/rack/security/advisories/GHSA-vpfw-47h7-xj4g> for the equivalent advisory in rack (affecting Rack < 3 only).

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity low, availability none.

Weakness class

CVE-2025-46336 is classified as CWE-362: Race Condition. Concurrent operations share state without proper synchronisation, so timing decides whether the result is correct.

Affected software

CVE-2025-46336 is recorded against 2 packages.

  • rack-session (from 2.0.0 up to 2.1.1)
  • unknown

Timeline and source

Published on 8 May 2025 and last revised on 4 February 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com (Web)
github.com (Web)
nvd.nist.gov (Advisory)
github.com (Web)
github.com (Package)
github.com (Web)

CVE-2025-46336 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Medium
CVSS Score 4.2
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
CWE CWE-362
Public Exploit ✅ No
Source NVD
Published 2025-05-08
Updated 2026-08-12
Modified 2026-02-04
Fix URL N/A

Affected Packages

Software From version Fixed in
rack-session 2.0.0 2.1.1
unknown — —

Similar Threats

Vulnerability Monitoring

Track new vulnerabilities in rack-session

CVE-2025-46336 is rated CVSS 4.2 Medium. BotEraser monitors your WordPress installation and notifies you when software you use appears in our vulnerability database.

Set Up Free Alerts →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.