WP Import – Ultimate CSV XML Importer for WordPress <= 7.35 - Authenticated (Contributor+) Server-Side Request Forgery via Bitly Shortlink Bypass

The WP Import – Ultimate CSV XML Importer for WordPress plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 7.35. This is due to inadequate validation of the resolved URL after following Bitly shortlink redirects in the `upload_function()` method. While the initial URL is validated using `wp_http_validate_url()`, when a Bitly shortlink is detected, the `unshorten_bitly_url()` function follows redirects to the final destination URL without re-validating it. This makes it possible for authenticated attackers with Contributor-level access or higher to make the server perform HTTP requests to arbitrary internal endpoints, including localhost, private IP ranges, and cloud metadata services (e.g., 169.254.169.254), potentially exposing sensitive internal data.