WP Meta SEO <= 4.5.18 - Authenticated (Contributor+) Server-Side Request Forgery via 'new_link' Parameter

The WP Meta SEO plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 4.5.18 via the 'new_link' parameter. This makes it possible for authenticated attackers, with contributor-level access and above, to make web requests to arbitrary locations originating from the web application and can be used to query and modify information from internal services. The HTTP response status from outbound requests is reflected back in the AJAX JSON response as status_code, providing an enumeration oracle usable for probing internal hosts and cloud metadata services.