A flaw was found in the Identity Provider (IdP) mapper component of Keycloak, which is used to manage how user information from external services is mapped to Keycloak users. An administrator with limited permissions to manage identity providers can exploit this flaw by creating a "Hardcoded Role" mapper that assigns high-level administrative roles (like realm-admin) to themselves or others. This allows a restricted administrator to bypass security checks and gain 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.