A flaw was found in the Keycloak package. This issue occurs due to a permissive regular expression hardcoded for filtering which allows hosts to register a dynamic client. A malicious user with enough information about the environment could jeopardize an environment with this specific Dynamic Client Registration and TrustedDomain configuration previously unauthorized.
Credits
Red Hat would like to thank Bastian Kanbach (Secure Systems DE [bastian.kanbach@securesystems.de]) for reporting this issue.