UserPro <= 5.1.1 - Cross-Site Request Forgery to Privilege Escalation

The UserPro plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 5.1.1. This is due to missing nonce validation in the 'admin_page', 'userpro_verify_user' and 'verifyUnverifyAllUsers' functions. This makes it possible for unauthenticated attackers to modify the role of verified users to elevate verified user privileges to that of any user such as 'administrator' via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.