CVE-2025-32441: Rack is a modular Ruby web server interface. Prior to version 2.2.14, when using the `Rack::Session::Pool` middleware, simultaneous rack requests can ...

Description

Rack is a modular Ruby web server interface. Prior to version 2.2.14, 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. Rack session middleware 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. 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. Version 2.2.14 contains a patch for the issue. Some other mitigations are available. Either ensure the 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.

Metrics

CVSS 3.1

4.2/10

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

EPSS Probability

0.19%

9.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Rack	Rack	< 2.2.14

References

https://github.com/rack/rack/blob/v2.2.13/lib/rack/session/abstract/id.rb#L263-L270Product
https://github.com/rack/rack/commit/c48e52f7c57e99e1e1bf54c8760d4f082cd1c89dPatch
https://github.com/rack/rack/security/advisories/GHSA-vpfw-47h7-xj4gMitigation, Vendor Advisory

Timeline

Published: May 7, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-32441?

Rack is a modular Ruby web server interface. Prior to version 2.2.14, 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. Rack session middleware 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. 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. Version 2.2.14 contains a patch for the issue. Some other mitigations are available. Either ensure the 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.

How severe is CVE-2025-32441?

CVE-2025-32441 has a CVSS score of 4.2/10 (MEDIUM severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.

How do I fix CVE-2025-32441?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.