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Session Fixation

CVE-2025-12390

Medium
6/10

Summary

A flaw was found in Keycloak version prior to 26.4.3. In Keycloak where a user can accidentally get access to another user's session if both use the same device and browser. This happens because Keycloak sometimes reuses session identifiers and doesn't clean up properly during logout when browser cookies are missing. As a result, one user may receive tokens that belong to another user.

  • HIGH
  • LOCAL
  • HIGH
  • UNCHANGED
  • REQUIRED
  • LOW
  • HIGH
  • NONE

CWE-384 - Session Fixation

Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.

References

Advisory Timeline

  • Published