CVE-2026-16621 Payment Gateway for PayPal on WooCommerce < 9.2.1 - Unauthenticated Payment Bypass via PayPal Advanced Return Handler
Unauthenticated attackers can mark arbitrary orders as paid without payment by bypassing verification in the PayPal return handler.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-16621?
CVE-2026-16621 is a medium-severity vulnerability in Unknown Payment Gateway for PayPal on WooCommerce, published on 12 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The Payment Gateway for PayPal on WooCommerce WordPress plugin before 9.2.1 does not verify that payment actually succeeded before completing an order in its PayPal return handler: it reads attacker-controlled parameters, performs no amount comparison and no order-ownership check, and completes the order even when the server-side gateway verification fails, allowing an unauthenticated attacker to mark arbitrary orders as paid without paying.
Which versions are affected by CVE-2026-16621?
How do I fix CVE-2026-16621?
No fix has been published for CVE-2026-16621 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-16621 being exploited?
There is no known exploitation of CVE-2026-16621 in the wild and no public exploit code.
Sources
Also known as GHSA-g8f7-gp6h-9f2x.