OpenCATS is an open-source applicant tracking system and recruitment CRM for staffing agencies and hiring teams. Prior to version 0.10.0, the Professional License configuration feature in SettingsUI (manageProfessional) accepts administrator-controlled license key input that is reconstructed into a PHP define() statement in config.php without safe escaping. Because the application includes config.php, crafted input can alter the file's PHP syntax and cause persistent arbitrary PHP execution with the web server process privileges. An authenticated administrator must have Settings module access and permission to update Professional License configuration, and config.php must be writable for this write-based path. Successful exploitation can read, modify or delete application data, expose…