The MF Gig Calendar WordPress plugin through 1.2.1 does not sanitise and escape some of its settings, which could allow high privilege users such as editor to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup)
https://wpscan.com/vulnerability/d34caeaf-2ecf-44a2-b308-e940bafd402c/