Subscribe Forms 1.4.1 - 1.6.2 - Author+ Stored XSS via Attention Effect Form Setting

The Subscribe Forms WordPress plugin before 1.6.3 does not sanitise and escape one of its form settings before outputting it in a page, allowing authenticated users with the Author role and above to perform Stored Cross-Site Scripting attacks that execute in the browser of any visitor who views a page embedding the form, including logged-out visitors and administrators.