The Social Pixel 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/02ca09f8-4080-4969-992d-0e6afb29bc62/