Checkout.com Payment Gateway <= 5.1.5 - Unauthenticated Missing Authorization to Order Modification via Flow AJAX and 3DS Handlers

Medium 6.5 CWE-862Fixed in 5.1.6
ID
WPSEC-2026-2806
Plugin
Checkout.com Payment Gateway (checkout-com-unified-payments-api)
Affected
from 5.0.0 before 5.1.6
Remediation
Update to 5.1.6 or later.
CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Weakness
CWE-862
Usage
Plugin Low · Affected versions None seen among sites WPSec scans, 2026-11-10
Attack surface
Checkout.com Payment Gateway on WPSec AttackSurface
Fix released
Published

Description

The Checkout.com Payment Gateway plugin for WordPress is vulnerable to Missing Authorization via the public Flow AJAX actions 'cko_flow_save_payment_session_id' and 'cko_flow_submit_payment_session' and the Flow 3DS return handler in all versions up to, and including, 5.1.5. This is due to missing order ownership checks on the 'order_id' parameter: guest orders were only required to be pending or failed, and the order key was optional. This makes it possible for unauthenticated attackers to act on other customers' pending or failed guest orders by ID: they can link their own payment sessions and payments to those orders, have them marked as failed, and get the order key back through the payment return URL, which exposes the order's details.

References

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