The OpenPGP Form Encryption for WordPress plugin before 1.5.1 does not validate and escape some of its shortcode attributes before outputting them back in a page/post where the shortcode is embed, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks.
https://wpscan.com/vulnerability/4e38c7d9-5b6a-4dfc-8f22-3ff30565ce43/