The Paid Membership Plugin, Ecommerce, User Registration Form, Login Form, User Profile & Restrict Content – ProfilePress plugin for WordPress is vulnerable to arbitrary shortcode execution in all versions up to, and including, 4.16.7 due to insufficient input sanitization on the `type` parameter in the form preview functionality. This makes it possible for authenticated attackers, with Subscriber-level access and above, to execute arbitrary shortcodes via the `pp_preview_form` endpoint.