# PDF Invoices & Packing Slips for WooCommerce <= 5.16.3 - Authenticated (Subscriber+) Missing Authorization to Order Information Disclosure via Document Number Preview

- **ID:** WPSEC-2026-0740
- **Plugin:** PDF Invoices & Packing Slips for WooCommerce (`woocommerce-pdf-invoices-packing-slips`), https://wordpress.org/plugins/woocommerce-pdf-invoices-packing-slips/
- **Affected versions:** all versions before 5.16.4
- **Fixed in:** 5.16.4 (Update to 5.16.4 or later.)
- **Severity:** Medium 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N)
- **Weakness:** CWE-862
- **Usage among sites WPSec scans:** plugin Low, affected versions None seen (as of 2026-10-10)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/woocommerce-pdf-invoices-packing-slips
- **Fix released:** 2026-10-08
- **Published:** 2026-10-10
- **URL:** https://wpsec.com/vuln/WPSEC-2026-0740/

## Description

The PDF Invoices & Packing Slips for WooCommerce plugin for WordPress is vulnerable to unauthorized access of data via the wpo_wcpdf_preview_formatted_number AJAX action in all versions up to, and including, 5.16.3, due to a missing capability check in the ajax_preview_formatted_number() function, which only verifies a nonce that is also handed to logged-in customers in their My Account document links. This makes it possible for authenticated attackers, with Subscriber-level access and above, to load arbitrary orders by ID and retrieve their order number and the order and document dates through the number format placeholders.

## References

- https://wpsec.com/vuln/WPSEC-2026-0740/
- https://plugins.svn.wordpress.org/woocommerce-pdf-invoices-packing-slips/tags/5.16.4/
- https://wordpress.org/plugins/woocommerce-pdf-invoices-packing-slips/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-0740/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.