Vulnerability Description
Rack::Session is a session management implementation for Rack. From 2.0.0 to before 2.1.2, Rack::Session::Cookie incorrectly handles decryption failures when configured with secrets:. If cookie decryption fails, the implementation falls back to a default decoder instead of rejecting the cookie. This allows an unauthenticated attacker to supply a crafted session cookie that is accepted as valid session data without knowledge of any configured secret. Because this mechanism is used to load session state, an attacker can manipulate session contents and potentially gain unauthorized access. This vulnerability is fixed in 2.1.2.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Rack | Rack-Session | >= 2.0.0, < 2.1.2 |
Related Weaknesses (CWE)
References
- https://github.com/rack/rack-session/security/advisories/GHSA-33qg-7wpp-89cqMitigationVendor Advisory
FAQ
What is CVE-2026-39324?
CVE-2026-39324 is a vulnerability with a CVSS score of 9.8 (CRITICAL). Rack::Session is a session management implementation for Rack. From 2.0.0 to before 2.1.2, Rack::Session::Cookie incorrectly handles decryption failures when configured with secrets:. If cookie decryp...
How severe is CVE-2026-39324?
CVE-2026-39324 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-39324?
Check the references section above for vendor advisories and patch information. Affected products include: Rack Rack-Session.