The WP Backpack WordPress plugin through 2.1 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)
https://wpscan.com/vulnerability/ce4688b6-6713-43b5-aa63-8a3b036bd332/