MemberPress <= 1.11.29 - Authenticated (Contributor+) Blind Server-Side Request Forgery via mepr-user-file Shortcode

The Memberpress plugin for WordPress is vulnerable to Blind Server-Side Request Forgery in all versions up to, and including, 1.11.29 via the 'mepr-user-file' shortcode. This makes it possible for authenticated attackers, with Contributor-level access and above, to make web requests to arbitrary locations originating from the web application and can be used to query and modify information from internal services.