The Themify Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via several parameters in all versions up to, and including, 7.6.9 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The vulnerability was partially patched in version 7.6.9.
https://plugins.trac.wordpress.org/changeset/3366817/
https://plugins.trac.wordpress.org/changeset/3355757/
https://plugins.trac.wordpress.org/browser/themify-builder/trunk/templates/template-icon.php#L95
https://plugins.trac.wordpress.org/browser/themify-builder/trunk/js/editor/build/modules.min.js