CVSS 4.0
6.3 mediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:NCVE-2026-121970
Medium (6.3). EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
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.
Severity
CVSS 3.1
3.7 lowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 8th percentile. Scored 2026-11-05. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-04. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-347 Improper Verification of Cryptographic Signature
- OWASP Top 10
- A04:2025 Cryptographic Failures
- Published
- Modified
- Record from
- the NVD, synced
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Explain CVE-2026-121970 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-121970?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-121970?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-121970 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| wphostingdev Pay with Vipps and MobilePay for WooCommerce | from 5.0.0 before 6.4.1 |
Attack patterns (CAPEC)
- CAPEC-463 Padding Oracle Crypto Attack Severity: High
- CAPEC-475 Signature Spoofing by Improper Validation Likelihood: Low · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.
References
- https://plugins.trac.wordpress.org/browser/woo-vipps/trunk/recurring/changelog.txt
- https://plugins.trac.wordpress.org/browser/woo-vipps/trunk/recurring/includes/wc-vipps-recurring.php
- https://wordpress.org/plugins/woo-vipps/#developers
- https://www.vulncheck.com/advisories/pay-with-vipps-and-mobilepay-for-woocommerce-before-webhook-signature-forgery