Vulnerability in N8n
CVE-2026-56357
n8n before 1.123.15 and 2.5.0 contains a webhook forgery vulnerability in the GitHub Webhook Trigger node that fails to implement HMAC-SHA256 signature verification. Attackers who know the webhook URL can send unsigned POST requests to trigger workflows with arbitrary data, spoofing GitHub webhook events.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.0 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (21.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 21.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- N8n — versions 0, 1.123.15, 2.0.0
Weakness classification (CWE)
References
- github.com/n8n-io/n8n/security/advisories/GHSA-mqpr-49jj-32rc (vendor-advisory, Vendor Advisory)
- www.vulncheck.com/advisories/n8n-webhook-forgery-via-missing-hmac-sha256-signat… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-56357?
- CVE-2026-56357 is a medium-severity vulnerability in N8n, classified under Authentication Bypass by Spoofing. CVSS score: 4.0/10. Published 2026-06-22.
- How severe is CVE-2026-56357?
- Medium severity. CVSS v3 base score is 4.0 out of 10.