Widget Shortcode <= 0.3.5 - 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.

Exploit shortcode:

[widget id='text-1' css_class='" onmouseover="alert(1)" style="background:red;width:300px;height:300px;']