GHSA-fm6w-rrp3-2x4w Keycloak Affected by Broken Access Control Vulnerability in the UserManagedPermissionService

• Maven org.keycloak:keycloak-services: < 26.2.13 → fixed in 26.2.13 • Maven org.keycloak:keycloak-services: >= 26.5.0, < 26.5.3 → fixed in 26.5.3 • Maven org.keycloak:keycloak-services: >= 26.3.0, < 26.4.9 → fixed in 26.4.9

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.