CVE-2026-39324
Publication date 7 April 2026
Last updated 16 April 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| ruby-rack | 25.10 questing |
Not affected
|
| 24.04 LTS noble |
Not affected
|
|
| 22.04 LTS jammy |
Not affected
|
|
| 20.04 LTS focal |
Not affected
|
|
| 18.04 LTS bionic |
Not affected
|
|
| 16.04 LTS xenial |
Not affected
|
|
| 14.04 LTS trusty |
Not affected
|
|
| ruby-rack-session | 25.10 questing |
Vulnerable
|
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release |
Notes
hlibk
Before ruby-rack version 3, the code was not split between ruby-rack and ruby-rack-session. Therefore, ruby-rack is affected for versions below 3. For versions of ruby-rack 3 or more, ruby-rack-session is affected instead.