Print-O-Matic < 2.1.8 - Contributor+ Stored XSS via Shortcode

The Print-O-Matic WordPress plugin before 2.1.8 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.