The SEO Redirection Plugin – 301 Redirect Manager WordPress plugin before 6.4 did not sanitise the Redirect From and Redirect To fields when creating a new redirect in the dashboard, allowing high privilege users (even with the unfiltered_html disabled) to set XSS payloads
https://wpscan.com/vulnerability/ca8068f7-dcf0-44fd-841d-d02987220d79