CVE-2026-39324
CRITICAL
INFO
Priority: 0.03
BB Relevance:
79/100
Published: 2026-04-07
Modified: 2026-10-26
First seen: 2026-10-29
Status: active
Attack Surface
Network
Low Complexity
No Auth
No Interaction
Conf. Impact
Integ. Impact
CVSS Vector Breakdown
AV:
Network
AC:
Low
PR:
None
UI:
None
S:
X
AT:
None
VC:
High
VI:
High
VA:
High
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.
Affected Software (1)
| Vendor | Product | Version |
|---|---|---|
| rack | rack-session | 2.0.0 – 2.1.2 |
References & Advisories (1)
Mitigation
Vendor Advisory