The WP Attachments WordPress plugin before 5.0.6 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/d3c39e17-1dc3-4275-97d8-543ca7226772