CVE-2025-32441 is a medium-severity (CVSS 4.2) CWE-362 vulnerability in rack. A fix is available for rack — see the affected versions and patch details below.
Rack session gets restored after deletion
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-32441.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
rackReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
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 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, or - Ensure your application invalidates sessions atomically by marking them as logged out e.g., using a
logged_outflag, 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
As this code was moved to rack-session in Rack 3+, see https://github.com/rack/rack-session/security/advisories/GHSA-9j94-67jr-4cqj for the equivalent advisory in rack-session (affecting Rack 3+ only).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | rack | all versions | 2.2.14bundle update rack --conservative |
Affected Products
rackrackDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rack, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rack to 2.2.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-32441 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2025-32441 in your dependencies?
Find it across RubyGems, including transitive dependencies.