The ClickSold IDX WordPress plugin through 1.90 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/198252c2-834b-401b-98a5-2f59910d67bc/