The Extensions For CF7 (Contact form 7 Database, Conditional Fields and Redirection) plugin for…

Why it is Amber

• CVSS 9.8 critical
• Remotely exploitable without logging in

References

• https://plugins.trac.wordpress.org/browser/extensions-for-cf7/tags/3.4.5/admin/include/class.cf7-signature.php#L222
• https://plugins.trac.wordpress.org/browser/extensions-for-cf7/tags/3.4.5/admin/include/class.cf7-signature.php#L82
• https://plugins.trac.wordpress.org/browser/extensions-for-cf7/tags/3.4.5/includes/class.cf7-extensions.php#L289
• https://plugins.trac.wordpress.org/browser/extensions-for-cf7/tags/3.4.5/includes/class.form-data-store.php#L42
• https://plugins.trac.wordpress.org/changeset/3727009/extensions-for-cf7/trunk/admin/include/class.cf7-signature.php
• https://plugins.trac.wordpress.org/changeset?reponame=&new=3727009%40extensions-for-cf7%2Ftags%2F3.4.6&old=3672142%40extensions-for-cf7%2Ftags%2F3.4.5
• https://www.wordfence.com/threat-intel/vulnerabilities/id/fa3193c4-dd3e-4d9e-be42-769c7358beae?source=cve

Original description

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.