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Improper Verification of Cryptographic Signature

CVE-2026-1529

High
8.1/10

Summary

A flaw was found in Keycloak in versions prior to 26.5.3. An attacker can exploit this vulnerability by modifying the organization ID and target email within a legitimate invitation token's JSON Web Token (JWT) payload. This lack of cryptographic signature verification allows the attacker to successfully self-register into an unauthorized organization, leading to unauthorized access.

  • LOW
  • NETWORK
  • HIGH
  • UNCHANGED
  • NONE
  • LOW
  • HIGH
  • NONE

CWE-347 - Improper Verification of Cryptographic Signature

A cryptographic protocol is meant to ensure that services are provided in a secure manner. An application with absent or improper verification of cryptographic signatures allows malicious users to feed false messages to valid users or to disclose sensitive data, subverting the goals of the protocol. This can lead to security failures such as false authentication, account hijacking, and privilege escalation.

References

Advisory Timeline

  • Published