The Paid Membership Plugin, Ecommerce, User Registration Form, Login Form, User Profile & Restrict Content WordPress plugin before 4.15.15 does not sanitise and escape some of its Drag & Drop Builder fields, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup).
https://wpscan.com/vulnerability/f7c3a990-458e-4e15-b427-0b37de120740/