The EventON WordPress plugin before 2.2.15 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/70d1f5d5-1a96-494b-9203-96a7780026da/