Critical advisory for The PDF Invoice for WooCommerce + Drag a

Advisory overview

The PDF Invoice for WooCommerce + Drag and Drop Template Builder plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 7.1.1 via the 'customer_note' parameter parameter. This is due to insufficient sanitization of the customer_note checkout field, which is inlined verbatim into invoice HTML, entity-decoded back into a live tag by simplehtmldom, reassembled into raw bytes by mPDF, and passed to unserialize() in _getObjAttr without validation. This makes it possible for unauthenticated attackers to execute code on the server. An unauthenticated attacker can trigger the vulnerable code path on a default install by placing an anonymous WooCommerce checkout via the public Store API (POST /wc/store/v1/checkout) using a Direct Bank Transfer or cheque payment method, which automatically transitions the order to 'on-hold' status and fires the plugin's invoice-generation hook.

Related references

• https://downloads.wordpress.org/plugin/pdf-for-woocommerce.7.2.0.zip
• https://plugins.trac.wordpress.org/browser/pdf-for-woocommerce/tags/7.1.1/frontend/index.php#L378
• https://plugins.trac.wordpress.org/browser/pdf-for-woocommerce/tags/7.1.1/libs/HtmlDocument.php#L300
• https://plugins.trac.wordpress.org/browser/pdf-for-woocommerce/tags/7.1.1/libs/HtmlNode.php#L1266
• https://plugins.trac.wordpress.org/browser/pdf-for-woocommerce/tags/7.1.1/vendor/mpdf/mpdf/src/Mpdf.php#L9105
• https://plugins.trac.wordpress.org/browser/pdf-for-woocommerce/tags/7.1.1/woocommerce/emails/index.php#L70
• https://plugins.trac.wordpress.org/browser/pdf-for-woocommerce/tags/7.1.1/woocommerce/shortcodes.php#L708
• https://www.wordfence.com/threat-intel/vulnerabilities/id/1bc3529c-6161-4b89-8a35-c3a9b7b8c308?source=cve