The ElementsKit Pro plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 's' parameter of the Advanced Search REST endpoint in all versions up to, and including, 4.10.1 due to insufficient input sanitization and output escaping. The REST endpoint at /wp-json/elementskit/v1/advanced-search uses permissioncallback set to returntrue, allowing unauthenticated access. Search terms are stored in the ekitadvancedsearchpopularkeyword WordPress option via updateoption(). While sanitizetextfield() is applied, it does not encode double quotes, and the stored keywords are rendered in HTML attributes via sprintf without escattr(), allowing attribute injection. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user triggers the "no results" popular keywords view on pages using the Advanced Search widget.

The ElementsKit Pro plugin for WordPress is vulnerable to DOM-Based Stored Cross-Site Scripting via the ‘url’ parameter in all versions up to, and including, 3.7.8 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.