The Favorites WordPress plugin before 2.3.5 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/47365daf-7ef5-471a-ab0e-f6d1b40ca56c/