VulnerabilityAnalyzed

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.

MEDIUM 6.3EPSS 0.31%

Does this matter?

Lower severity and a low EPSS score (0.31%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 4.0: 6.3 MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.31% probability · 24th percentile
CISA KEV: Not listed
Weakness: CWE-290
Affected: n8n/n8n
Source: disclosure@vulncheck.com

References

https://github.com/n8n-io/n8n/security/advisories/GHSA-mqpr-49jj-32rcVendor Advisory
https://www.vulncheck.com/advisories/n8n-webhook-forgery-via-missing-hmac-sha256-signature-verification-in-github-webhook-triggerThird Party Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.