A Stored XSS vulnerability was reported in the Keycloak Security mailing list, affecting all the versions of Keycloak, including the latest release (16.0.1). The vulnerability allows a privileged attacker to execute malicious scripts in the admin console, abusing of the groups' dropdown functionality.
Successful attacks of this vulnerability can result a privileged attacker to load a XSS script, and steal data from other users. The impact can be considered moderate to low, considering privileged credentials are required.