Admidio is a free, open source user management system for websites of organizations and groups. In Admidio before version 4.3.9, there is an SQL Injection in the `/adm_program/modules/ecards/ecard_send.php` source file of the Admidio Application. The SQL Injection results in a compromise of the application's database. The value of `ecard_recipients `POST parameter is being directly concatenated with the SQL query in the source code causing the SQL Injection. The SQL Injection can be exploited by a member user, using blind condition-based, time-based, and Out of band interaction SQL Injection payloads. This vulnerability is fixed in 4.3.9.