CVE-2026-56357: n8n - Webhook Forgery via Missing HMAC-SHA256 Signature Verification in GitHub Webhook Trigger
Medium · CVSS 4.0 (CVSS 3.1)EPSS 0.31%, 24th percentilePublished Updated Assigner: VulnCheck
Description
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.
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N · CWE-290
Tracked companies
Mapped from the CVE’s affected-product data, NVD CPE matches, vendor advisories or package feeds. A mapping means the vendor’s software is named, not that its hosted service was exposed.
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
n8n: n8n
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- github.com/n8n-io/n8n/security/advisories/GHSA-mqpr-49jj-32rc (opens in new tab)
- www.vulncheck.com/advisories/n8n-webhook-forgery-via-missing-hmac-sha256-signature-veri… (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)