The Breadcrumb NavXT plugin for WordPress is vulnerable to authorization bypass through user-controlled key in versions up to and including 7.5.0. This is due to the Gutenberg block renderer trusting the $_REQUEST['post_id'] parameter without verification in the includes/blocks/build/breadcrumb-trail/render.php file. This makes it possible for unauthenticated attackers to enumerate and view breadcrumb trails for draft or private posts by manipulating the post_id parameter, revealing post titles and hierarchy that should remain hidden.