A remote code execution vulnerability has been identified in the User Defined Tags module of CMS Made Simple version 2.2.19 / 2.2.21. This vulnerability arises from inadequate sanitization of user-supplied input in the 'Code' section of the module. As a result, authenticated users with administrative privileges can inject and execute arbitrary PHP code.
https://packetstormsecurity.com/files/177241/CMS-Made-Simple-2.2.19-Remote-Code-Execution.html