Advanced Import: One-Click Demo Import for WordPress <= 1.4.6 - Authenticated (Author+) Server-Side Request Forgery via 'demo_file' Parameter

The Advanced Import plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 1.4.6. This is due to the plugin using wp_remote_get() to fetch a user-supplied URL without validating that the URL does not point to internal or private network resources in the demo_download_and_unzip() function. The 'demo_file' parameter from $_POST is passed through sanitize_text_field() (which only handles XSS-related sanitization) and then directly into wp_remote_get() when 'demo_file_type' is set to 'url'. Notably, the plugin uses wp_safe_remote_get() in other locations (theme template libraries) which would provide SSRF protection, but fails to use it in this critical AJAX handler. This makes it possible for authenticated attackers, with Author-level access and above (upload_files capability), to make web requests to arbitrary locations originating from the web application, which can be used to query and view data from internal services, including cloud instance metadata endpoints.