The PVN Auth Popup WordPress plugin through 1.0.0 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/7d28ea72-8c3b-4607-b877-7b10d954fef9/