The Advanced Contact Form 7 - Compact DB plugin for WordPress is vulnerable to unauthorized deletion of data due to a missing capability check on the cf7cdb_ajax_delete_user() function in versions up to, and including, 1.0.0. The handler is registered against both `wp_ajax_cf7cdb_delete` and `wp_ajax_nopriv_cf7cdb_delete`, and it performs no nonce verification, no capability check, and no ownership check before invoking `$wpdb->delete()` against the `wp_cf7cdb_data` table with an attacker-supplied integer ID. This makes it possible for unauthenticated attackers to delete arbitrary contact form submission entries stored by the plugin by iterating sequential primary-key IDs.