UserPro <= 5.1.1 - Cross-Site Request Forgery to Sensitive Information Exposure

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 or incorrect nonce validation on the 'export_users' function. This makes it possible for unauthenticated attackers to export the users to a csv file, granted they can trick a site administrator into performing an action such as clicking on a link.