The NextCellent Gallery WordPress plugin through 1.9.35 does not sanitise and escape some of its image 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/1bffbbef-7876-43a6-9cb0-6e09bb4ff2b0