Keycloak vulnerable to session hijacking via re-authentication

A flaw was found in Keycloak. An active keycloak session can be hijacked by initiating a new authentication (having the query parameter prompt=login) and forcing the user to enter his credentials once again. If the user cancels this re-authentication by clicking Restart login, the account takeover could take place as the new session, with a different SUB, will have the same SID as the previous session.