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, 2.12.10. This is due to missing nonce validation on the pmproliftersavestreamlineoption() function. This makes it possible for unauthenticated attackers to enable the streamline setting with Lifter LMS via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.