The Quick Subscribe WordPress plugin through 1.7.1 does not have CSRF check in place when updating its settings, which could allow attackers to make a logged in admin change them via a CSRF attack and leading to Stored XSS due to the lack of sanitisation and escaping in some of them
https://wpscan.com/vulnerability/44555c79-480d-4b6a-9fda-988183c06909