CVE-2026-19991: falha de alta gravidade em stiofansisland UsersWP – Front-end login form…

The UsersWP plugin for WordPress is vulnerable to Arbitrary File Deletion in versions up to, and including, 1.2.70 via the upload_file_remove() AJAX handler. The plugin stores the value of an account 'file' form field taken directly from $_POST when no real $_FILES upload is provided (process_account() calls uwp_validate_fields() and array_merges the result with the empty output of UsersWP_Files::validate_uploads()). At storage time the value is only checked with validate_file(), which passes any string that does not contain a literal '../'. When the value is later processed by upload_file_remove(), it is again gated with validate_file() and then normalized through uwp_get_file_relative_url(); that helper performs a global str_replace() of the uploads base URL against the stored URL, allowing a crafted URL containing embedded '..<uploads-baseurl>' tokens to collapse into '../../' traversal sequences after the last validation. The transformed value is then appended to the uploads base directory and passed to wp_delete_file() without any canonical containment check. This makes it possible for authenticated attackers, with Subscriber-level access and above, to delete arbitrary files on the affected site's server (including wp-config.