The Soumettre.fr plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the soumettre_disconnect_gateway function in all versions up to, and including, 2.1.2. This makes it possible for authenticated attackers, with Subscriber-level access and above, to disconnect the gateway and delete the API key.
https://plugins.trac.wordpress.org/browser/soumettre-fr/trunk/admin/class-soumettre-admin.php#L276