A flaw was found in Keycloak. A limited administrator can exploit an improper access control vulnerability in the POST /admin/realms/{realm}/partialImport endpoint. This allows them to bypass Fine-Grained Admin Permissions (FGAP) and escalate their privileges to a full realm administrator by importing users with realm-admin role mappings.
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.