Contao has improper access control in the back end voters

Contao is an Open Source CMS. In versions starting from 5.0.0 and prior to 5.3.38 and 5.6.1, the table access voter in the back end doesn't check if a user is allowed to access the corresponding module. This issue has been patched in versions 5.3.38 and 5.6.1. A workaround involves not relying solely on the voter and additionally to check USER_CAN_ACCESS_MODULE.