ChurchCRM is an open-source church management system. In versions prior to 6.5.3, a SQL injection vulnerability in ChurchCRM's Event Attendee Editor allows authenticated users to execute arbitrary SQL commands, leading to complete database compromise, administrative credential theft, and potential system takeover. The vulnerability enables attackers to extract sensitive member data, authentication credentials, and financial information from the church management system. Version 6.5.3 contains a patch for the issue.