6.3
MEDIUM CVSS 4.0
CVE-2026-121970
Pay with Vipps and MobilePay for WooCommerce before 6.4.1 Webhook Signature Forgery
Description

Pay with Vipps and MobilePay for WooCommerce (woo-vipps) before 6.4.1 contains an improper cryptographic signature verification vulnerability in the recurring-payment webhook handler that allows unauthenticated attackers to forge webhook requests when no local webhook secret is stored, because the code fails to return on an empty secret and computes an HMAC keyed with an empty string using a loose == comparison instead of hash_equals. Attackers can craft a recurring.agreement-stopped.v1 event with a known agreementId and a matching empty-key signature to cancel a victim's active WooCommerce subscription.

INFO

Published Date :

Nov. 4, 2026, 1:17 p.m.

Last Modified :

Nov. 4, 2026, 1:17 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-121970 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 LOW 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 3.1 LOW [email protected]
CVSS 4.0 MEDIUM 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 MEDIUM [email protected]
Solution
Update the plugin to version 6.4.1 or later to fix a cryptographic signature verification flaw.
  • Update the woo-vipps plugin to version 6.4.1 or newer.
  • Configure a local webhook secret if not already set.
  • Verify webhook handler logic for empty secret comparison.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-121970 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-121970 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-121970 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-121970 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Nov. 04, 2026

    Action Type Old Value New Value
    Added Description Pay with Vipps and MobilePay for WooCommerce (woo-vipps) before 6.4.1 contains an improper cryptographic signature verification vulnerability in the recurring-payment webhook handler that allows unauthenticated attackers to forge webhook requests when no local webhook secret is stored, because the code fails to return on an empty secret and computes an HMAC keyed with an empty string using a loose == comparison instead of hash_equals. Attackers can craft a recurring.agreement-stopped.v1 event with a known agreementId and a matching empty-key signature to cancel a victim's active WooCommerce subscription.
    Added CVSS V4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
    Added CWE CWE-347
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/121xxx/CVE-2026-121970.json">CVE-2026-121970</a>
    Added Reference https://plugins.trac.wordpress.org/browser/woo-vipps/trunk/recurring/changelog.txt
    Added Reference https://plugins.trac.wordpress.org/browser/woo-vipps/trunk/recurring/includes/wc-vipps-recurring.php
    Added Reference https://wordpress.org/plugins/woo-vipps/#developers
    Added Reference https://www.vulncheck.com/advisories/pay-with-vipps-and-mobilepay-for-woocommerce-before-webhook-signature-forgery
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.