Cool FormKit Lite <= 2.7.9 - Authenticated (Contributor+) Stored DOM-Based Cross-Site Scripting via Form Field custom_id Parameter

The Cool FormKit Lite – Advanced Form Builder for Elementor plugin for WordPress is vulnerable to Stored DOM-Based Cross-Site Scripting via the '_elementor_data.form_fields[].custom_id' parameter in all versions up to, and including, 2.7.9 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 esc_html() call applied at server emission is bypassed because the HTML fragment-serialization algorithm restores &quot; to a raw double-quote inside text nodes when jQuery .html() extracts the template, allowing the attacker-controlled custom_id to break out of an HTML attribute context within the plugin's own frontend script.