MW WP Form <= 5.1.3 - Authenticated (Editor+) Stored Cross-Site Scripting via 'memo' Parameter

The MW WP Form plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'memo' parameter in all versions up to, and including, 5.1.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with editor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Because the memo value is stored via update_post_meta() rather than wp_insert_post(), WordPress's built-in kses and unfiltered_html protections do not apply, allowing attackers to break out of the textarea element via injected closing tags regardless of role-based content filtering.