The SurfLink - Ultimate Link Manager plugin for WordPress is vulnerable to unauthorized data modification due to a missing capability check on the ajax_import_410() function in all versions up to 2.6.0. This is due to a missing capability check (current_user_can()) and missing nonce verification (check_ajax_referer()) in the ajax_import_410() function, while all other AJAX handlers in the same class (ajax_add_single_410, ajax_save_editted_410, ajax_delete_410, ajax_bulk_410_delete, ajax_empty_410, ajax_export_410) properly implement both authorization and nonce checks. This makes it possible for authenticated attackers, with Subscriber-level access and above, to import arbitrary URLs into the 410 Gone database table via the surfl_import_410 AJAX action. Injected URLs will cause the site to return HTTP 410 Gone responses to all visitors accessing those paths, potentially causing denial of service for legitimate pages and SEO damage through search engine delisting.