Affected: Red Hat Build of Keycloak, Red Hat Data Grid 8, Red Hat JBoss Enterprise Application Platform Expansion Pack, Red Hat Single Sign-On 7

A flaw was found in the group policy evaluation logic of Keycloak, an identity and access management solution. When a group policy is set to extend permissions to child groups, the system incorrectly uses a simple text-based prefix check to verify group membership. This allows a user who belongs to a different group with a similar starting name to bypass security checks and gain unauthorized access to administrative functions or protected resources.