# Extra Fees for WooCommerce <= 4.4.0 - Authenticated (Contributor+) PHP Object Injection via Fee Rule Post Meta

- **ID:** WPSEC-2026-2970
- **Plugin:** Extra Fees for WooCommerce (`woo-conditional-product-fees-for-checkout`), https://wordpress.org/plugins/woo-conditional-product-fees-for-checkout/
- **Affected versions:** all versions before 4.4.1
- **Fixed in:** 4.4.1 (Update to 4.4.1 or later.)
- **Severity:** High 8.8 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **Weakness:** CWE-502
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-11-12)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/woo-conditional-product-fees-for-checkout
- **Fix released:** 2026-11-11
- **Published:** 2026-11-12
- **URL:** https://wpsec.com/vuln/WPSEC-2026-2970/

## Description

The Extra Fees for WooCommerce plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 4.4.0 via deserialization of fee rule post meta (such as 'cost_rule_match', 'product_fees_metabox' and 'ds_select_day_of_week') with maybe_unserialize(). The fee custom post type was registered without capability restrictions and its meta keys were not protected, so low-privileged users could write serialized payloads into fee meta, for example via XML-RPC custom fields. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject a PHP Object. No known POP chain is present in the vulnerable software itself; if a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.

Also published later by wordfence as CVE-2026-116866.

## References

- https://wpsec.com/vuln/WPSEC-2026-2970/
- https://plugins.svn.wordpress.org/woo-conditional-product-fees-for-checkout/tags/4.4.1/
- https://wordpress.org/plugins/woo-conditional-product-fees-for-checkout/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-2970/

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.