The Invitation Based Registrations WordPress plugin through 2.2.84 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 when the unfiltered_html capability is disallowed (for example in multisite setup)
https://wpscan.com/vulnerability/c8dcd7a7-5ad4-452c-a6a5-2362986656e4