The WANotifier WordPress plugin before 2.6.1 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/b9e6648a-9d19-4e73-ad6c-f727802d8dd5/