King Addons for Elementor < 51.1.63 - Authenticated (Subscriber+) Stored Cross-Site Scripting via 'form_page_id' Parameter

Description

The King Addons for Elementor plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'form_page_id' parameter in versions up to, and including, 51.1.62 This is due to insufficient input sanitization in the add_to_submissions() function, which applies sanitize_text_field() (which preserves double-quote characters) before storing the value in post meta, combined with missing output escaping in the king_addons_submissions_custom_column_content() function, which concatenates the stored value into an HTML href attribute via admin_url() without wrapping the result in esc_url(). This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.