## https://sploitus.com/exploit?id=WPEX-ID:38053E05-4B17-4FA9-ACD3-85D8529B202B
Put the following payload in the Button text setting of the plugin (in the Notice Setting section)
" style=animation-name:twentytwentyone-close-button-transition onanimationend=alert(/XSS/)//
"onmouseover=alert(/XSS/)//
Then go on any page of the frontend to trigger the XSS (which may require some user interaction depending on the payload/theme used)