CVE-2026-4636

Summary

A flaw was found in Keycloak. An authenticated user with the uma_protection role can bypass User-Managed Access (UMA) policy validation. This allows the attacker to include resource identifiers owned by other users in a policy creation request, even if the URL path specifies an attacker-owned resource. Consequently, the attacker gains unauthorized permissions to victim-owned resources, enabling them to obtain a Requesting Party Token (RPT) and access sensitive information or perform unauthorized actions.

Affected Software

VendorProductVersion RangeStatus
Red HatRed Hat build of Keycloak 26.226.2.15-1 < *unaffected
Red HatRed Hat build of Keycloak 26.226.2-18 < *unaffected
Red HatRed Hat build of Keycloak 26.226.2-18 < *unaffected
Red HatRed Hat build of Keycloak 26.426.4.11-1 < *unaffected
Red HatRed Hat build of Keycloak 26.426.4-14 < *unaffected
Red HatRed Hat build of Keycloak 26.426.4-14 < *unaffected

Weaknesses

  • CWE-551: Incorrect Behavior Order: Authorization Before Parsing and Canonicalization

Workarounds

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: total

keycloak: Keycloak: UMA policy bypass allows authenticated users to gain unauthorized access to victim-owned resources.

Additional References

References