The User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Avatar Field in all versions up to, and including, 4.0.2 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This is exploitable via a nonce-free GET request to /wp-admin/profile.php, requiring no profile-form submission; a Subscriber can plant the malicious attachment URL, which then executes when an administrator opens that user's Edit User screen.