The Sailthru Triggermail WordPress plugin through 1.1 does not sanitise and escape some of its settings and is missing CSRF protection which could allow subscribers to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup).
https://wpscan.com/vulnerability/6fe3544b-fb86-43e4-9771-6e9343f9f835/