The User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'email' parameter in all versions up to, and including, 4.0.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The payload reaches administrators with the manage_options capability when they visit the Users > Unconfirmed Email Addresses list table and interact with row-action links, as the poisoned javascript: href is rendered verbatim into the page HTML by row_actions().