Divi Form Builder <= 5.1.2 - Unauthenticated Privilege Escalation via 'role'

The Divi Form Builder plugin for WordPress is vulnerable to privilege escalation in versions up to, and including, 5.1.2. This is due to the plugin accepting a user-controlled 'role' parameter from POST data during user registration without validating it against the form's configured default_user_role setting. This makes it possible for unauthenticated attackers to create administrator accounts by tampering with the role parameter during registration.