CVE-2026-39324 (GCVE-0-2026-39324)

Vulnerability from cvelistv5 – Published: 2026-04-07 18:13 – Updated: 2026-04-08 18:44
VLAI?
Title
Rack::Session::Cookie secrets: decrypt failure fallback enables secretless session forgery and Marshal deserialization
Summary
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.
CWE
  • CWE-287 - Improper Authentication
  • CWE-345 - Insufficient Verification of Data Authenticity
  • CWE-502 - Deserialization of Untrusted Data
  • CWE-565 - Reliance on Cookies without Validation and Integrity Checking
Assigner
References
Impacted products
Vendor Product Version
rack rack-session Affected: >= 2.0.0, < 2.1.2
Create a notification for this product.
Show details on NVD website

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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