Soumettre.fr <= 2.1.5 - Improper Authorization to Unauthenticated Soumettre Posts Creation/Modification/Deletion

The Soumettre.fr plugin for WordPress is vulnerable to unauthorized access and modification of data due to a improper authorization checks on the make_signature function in all versions up to, and including, 2.1.5. This makes it possible for unauthenticated attackers to create/edit/delete Soumettre posts. This vulnerability affects only installations where the soumettre account is not connected (i.e. API key is not installed)