Keycloak Affected by Broken Access Control Vulnerability in the UserManagedPermissionService
Moderate severity
GitHub Reviewed
Published
Feb 9, 2026
to the GitHub Advisory Database
•
Updated Feb 13, 2026
Package
Affected versions
< 26.2.13
>= 26.5.0, < 26.5.3
>= 26.3.0, < 26.4.9
Patched versions
26.2.13
26.5.3
26.4.9
Description
Published by the National Vulnerability Database
Feb 9, 2026
Published to the GitHub Advisory Database
Feb 9, 2026
Reviewed
Feb 10, 2026
Last updated
Feb 13, 2026
A flaw was found in Keycloak. A significant Broken Access Control vulnerability exists in the UserManagedPermissionService (UMA Protection API). When updating or deleting a UMA policy associated with multiple resources, the authorization check only verifies the caller's ownership against the first resource in the policy's list. This allows a user (Owner A) who owns one resource (RA) to update a shared policy and modify authorization rules for other resources (e.g., RB) in that same policy, even if those other resources are owned by a different user (Owner B). This constitutes a horizontal privilege escalation.
References