The Sticky Side Buttons WordPress plugin before 2.0.0 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/c37f1708-c154-41dc-9079-3230827eed1b/