Mesmerize Companion < 1.6.135 - Contributor+ Stored XSS

The plugin 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.

PoC

Required theme: https://wordpress.org/themes/mesmerize (the shortcode is added only if this theme is used) Exploit shortcode: [mesmerize_latest_news item_class=‘" onmouseover="alert(1)’]