Auth bypass in Strablengineering Strabl – A Checkout Solution

CVE-2026-3640

The STRABL – A checkout solution plugin for WordPress is vulnerable to Missing Authentication in all versions up to and including 4.5. The plugin registers a REST API webhook endpoint at /wp-json/strabl/webhook/order with a permission_callback of __return_true, which allows all incoming requests without any authentication or authorization checks. No shared secret, signature validation, HMAC verification, or token-based authentication is implemented. This makes it possible for unauthenticated attackers to create fraudulent WooCommerce orders and mark them as completed by supplying paymentStatus=paid, manipulate existing order statuses by providing an externalOrderId, create new WordPress user accounts with the customer role, issue refunds on existing orders, cancel existing orders, and apply chargeback fees — all without making a legitimate payment or having any valid credentials.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.006 (48.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-3640: held from 0.006 to 0.006.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-3640?
CVE-2026-3640 is a medium-severity vulnerability in Strablengineering Strabl – A Checkout Solution, classified under Missing Authorization. CVSS score: 5.3/10. Published 2026-06-19.
How severe is CVE-2026-3640?
Medium severity. CVSS v3 base score is 5.3 out of 10.