Tiare Membership <= 1.2 - Unauthenticated Privilege Escalation

The Tiare Membership plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 1.2. This is due to the 'tiare_membership_init_rest_api_register' function not restricting what user roles a user can register with. This makes it possible for unauthenticated attackers to supply the 'administrator' role during registration and gain administrator access to the site.