The plugin does not sanitise or escape its Category Names before outputting them in page/post where the associated shortcode is embed, allowing high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html is disallowed
Create a new category via the plugin (/wp-admin/admin.php?page=owaccategory), add the following payload in the Name field: , then view a page/post where the associated Category Shortcode is embed