MetForm < 4.1.9 - Contributor+ Stored XSS via 'mf_form_id' Widget Setting

Description

The plugin is vulnerable to Stored Cross-Site Scripting via the 'mf_form_id' Widget Setting due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The payload bypasses Elementor's save-time wp_kses_post filter because it contains no HTML tags, and the plugin's own str_replace transformation of script tags into JavaScript template literal expressions provides an additional delivery path.