The Extensions For CF7 (Contact form 7 Database, Conditional Fields and Redirection) plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 3.4.5 via the extcf7_submit function. This is due to missing file extension, MIME type, and size validation in the signature field's validation_filter(), combined with the absence of PHP-execution guards in the upload directory and a sanitize_file_name() bypass that converts shell.php- into shell.php. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible.