Tag Groups < 2.2.0 - Reflected XSS via 'tag_groups_task' Parameter

The Tag Groups is the Advanced Way to Display Your Taxonomy Terms WordPress plugin before 2.2.0 does not properly escape one of its AJAX parameters before reflecting it in the response body served with an HTML content type, allowing unauthenticated attackers to execute arbitrary JavaScript in the browser of a logged-in user with edit_pages capability (Editor or higher) who is tricked into following a crafted link.