The Smart Floating / Sticky Buttons WordPress plugin before 2.5.5 does not sanitise and escape some parameter before outputting them in attributes and page, which could allow high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed.
https://wpscan.com/vulnerability/db0b9480-2ff4-423c-a745-68e983ffa12b