The Sitemap WordPress plugin before 4.4 does not validate and escape some of its shortcode attributes before outputting them back in the page, which could allow users with a role as low as contributor to perform Stored Cross-Site Scripting attacks which could be used against high privilege users such as admins.
https://wpscan.com/vulnerability/19f482cb-fcfd-43e6-9a04-143e06351a70