What is CVE-2026-103331?

CVE-2026-103331 is a medium-severity vulnerability in Unipay Payment Gateway For Woocommerce, classified under Improper Authentication. CVSS score: 5.3/10. Published 2026-10-28.

How severe is CVE-2026-103331?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Auth bypass in Unipay Payment Gateway For Woocommerce

CVE-2026-103331

The UniPAY Payment Gateway For WooCommerce WordPress plugin through 2.3 does not properly verify the authenticity of payment notifications, as their signature is checked against a merchant secret that is empty by default, allowing unauthenticated attackers to forge a valid notification and mark arbitrary orders as paid.

Vulnerability class: Broken Authentication

Published 2026-10-28 · last modified 2026-10-28.

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: 0.002 (4.4th percentile), scored 2026-10-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 4th percentile — 4.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

The 30-day trend appears once there are two daily scores.

Affected products

Unipay Payment Gateway For Woocommerce

Weakness classification (CWE)

CWE-287 — Improper Authentication

References

wpscan.com/vulnerability/a7d61b5f-9e92-459c-8f6d-1c92ea94ef00/ (technical-description, exploit, vdb-entry)

Frequently asked questions

What is CVE-2026-103331?: CVE-2026-103331 is a medium-severity vulnerability in Unipay Payment Gateway For Woocommerce, classified under Improper Authentication. CVSS score: 5.3/10. Published 2026-10-28.
How severe is CVE-2026-103331?: Medium severity. CVSS v3 base score is 5.3 out of 10.