The Gum Addon for Elementor plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'pop_tag' parameter in all versions up to, and including, 1.3.15 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.
https://plugins.trac.wordpress.org/browser/gum-elementor-addon/trunk/widgets/popover_btn.php#L767
https://plugins.trac.wordpress.org/browser/gum-elementor-addon/trunk/widgets/popover_btn.php#L726