Responsive Gallery Grid < 2.3.11 - Admin+ Stored XSS

Description The plugin does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup)

PoC

1. Navigate to “RGG Gallery” and scroll down to “General Settings” 2. Change “Class” field to (" onmouseover='alert(1)') 3. Save setting and see the XSS when you mouseover the “Class” field