CRMEB LoginController.php appleLogin improper authentication

A security flaw has been discovered in CRMEB up to 5.6.3. The affected element is the function appleLogin of the file crmeb/app/api/controller/v1/LoginController.php. Performing a manipulation of the argument openId results in improper authentication. The attack is possible to be carried out remotely. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.