Not Failing Securely ('Failing Open') Affecting rack-session package, versions >=2.0.0, <2.1.2
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Test your applications- Snyk IDSNYK-RUBY-RACKSESSION-15928857
- published8 Apr 2026
- disclosed8 Apr 2026
- creditSeungMyung Lee
Introduced: 8 Apr 2026
NewCVE-2026-39324 (opens in a new tab)Common Vulnerabilities and Exposures (CVE) are common identifiers for publicly known security vulnerabilities
Common Weakness Enumeration (CWE) is a category system for software weaknesses
How to fix?
Upgrade rack-session to version 2.1.2 or higher.
Overview
rack-session is a session implementation for Rack.
Affected versions of this package are vulnerable to Not Failing Securely ('Failing Open') in the Rack::Session::Cookie() function when it is configured with the secrets: option. An attacker can gain unauthorized access or escalate privileges by supplying a crafted session cookie that if decryption fails is accepted as valid.