Metform Elementor Contact Form Builder <= 3.3.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via mf_thankyou shortcode

The Metform Elementor Contact Form Builder for WordPress is vulnerable to Cross-Site Scripting by using the 'fname' attribute of the 'mf_thankyou' shortcode to echo unescaped form submissions in versions up to, and including, 3.3.0. This allows authenticated attackers, with contributor-level permissions or above, to inject arbitrary web scripts in pages that will execute when the victim visits a a page containing the shortcode when the submission id is present in the query string. Note that getting the JavaScript to execute requires user interaction as the victim must visit a crafted link with the form entry id, but the script itself is stored in the site database. Additionally this requires successful payment, increasing the complexity.