Masteriyo LMS <= 2.1.6 - Missing Authorization to Authenticated (Student+) Privilege Escalation to Administrator

The Masteriyo LMS plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 2.1.6. This is due to the plugin allowing a user to update the user role through the 'InstructorsController::prepare_object_for_database' function. This makes it possible for authenticated attackers, with Student-level access and above, to elevate their privileges to that of an administrator.