The Paid Memberships Pro – Content Restriction, User Registration, & Paid Subscriptions plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 3.0.1. This is due to missing or incorrect nonce validation on the pmpro_update_level_group_order() function. This makes it possible for unauthenticated attackers to update order levels via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.