The WP Live Chat Support plugin before 8.0.06 for WordPress has stored XSS via the Name field.
https://www.youtube.com/watch?v=eHG1pWaez9w
https://www.gubello.me/blog/wp-live-chat-support-8-0-05-stored-xss/
https://wordpress.org/plugins/wp-live-chat-support/#developers