A flaw was found in the Admin REST API of Keycloak, an open-source identity and access management solution. The issue occurs in the group-membership endpoints where the system fails to check if a group grants administrative privileges before allowing a user to be added. This allows a delegated administrator with limited permissions to add themselves to a high-privilege group, potentially gaining full control over the entire realm.
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.