The LetterPress WordPress plugin before 2.4.0 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/8e3291be-265c-4dec-876c-3e8e3ec0443a/