e107 is a content management system (CMS). Prior to 2.3.7, the bundled alt_auth plugin's otherdb and e107db authentication backends interpolate the submitted login username directly into SQL in e107_plugins/alt_auth/otherdb_auth.php and e107_plugins/alt_auth/e107db_auth.php. The login() methods execute those strings with PDO::query() before effective sanitization, so an unauthenticated user can inject SQL when alt_auth is installed and either backend is configured with a live external database connection. The injection can expose or modify data available to the configured database account, and query failures can additionally disclose the generated query through the debug-message path. This issue is fixed in version 2.3.7.