The Lightbox & Modal Popup WordPress Plugin WordPress plugin before 2.7.28, foobox-image-lightbox-premium WordPress plugin before 2.7.28 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/996d3247-ebdd-49d1-a1a3-ceedcf9f2f95/