CVE Vulnerabilities

CVE-2026-39324

Improper Authentication

Published: Apr 07, 2026 | Modified: Apr 15, 2026
CVSS 3.x
9.8
CRITICAL
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
Ubuntu
MEDIUM
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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.

Weakness

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

Affected Software

NameVendorStart VersionEnd Version
Rack-sessionRack2.0.0 (including)2.1.2 (excluding)
Ruby-rack-sessionUbuntudevel*
Ruby-rack-sessionUbuntuquesting*
Ruby-rack-sessionUbunturesolute*
Ruby-rack-sessionUbuntuupstream*

Potential Mitigations

References