GiveWP <= 4.16.3 - Authenticated (Give Worker+) Stored Cross-Site Scripting via 'twitter_message' Sequoia Template Setting

The GiveWP – Donation Plugin and Fundraising Platform plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'twitter_message' Sequoia Template Setting in all versions up to, and including, 4.16.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with give worker-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The injected script executes specifically when a donor clicks the Share on Twitter button on the Sequoia donation confirmation view, as that is when the unescaped twitter_message value is evaluated inside the JavaScript template literal.