The Subscribe2 WordPress plugin before 10.46 does not properly escape a user-supplied value before reflecting it into a public subscription form, leading to Reflected Cross-Site Scripting that executes in the browser of an unauthenticated visitor who interacts with the form through a crafted link.
https://wpscan.com/vulnerability/5ea58741-0c4c-4482-94dd-34721b19fc26/