What’s Vulnerable › Vulnerabilities

CVE-2026-56357: n8n - Webhook Forgery via Missing HMAC-SHA256 Signature Verification in GitHub Webhook Trigger

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-22 · updated 2026-06-24
• Weakness: CWE-290

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.

Affected products

• n8n-io n8n: before 1.123.15; from 2.0.0 before 2.5.0 — fixed in 1.123.15, 2.5.0

How to fix

Upgrade to a fixed version: n8n-io n8n 1.123.15, 2.5.0. Check the vendor advisory for mitigations.

References

• https://github.com/n8n-io/n8n/security/advisories/GHSA-mqpr-49jj-32rc
• https://www.vulncheck.com/advisories/n8n-webhook-forgery-via-missing-hmac-sha256-signature-verification-in-github-webhook-trigger

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