CVE-2026-56360: n8n - Webhook Forgery via Unsigned POST Requests in ZendeskTrigger

Severity: medium (CVSS 4.0 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: 2026-07-08 · updated 2026-10-25
Weakness: CWE-290

Description

n8n before versions 1.123.18 and 2.6.2 fails to verify HMAC-SHA256 signatures on Zendesk webhooks in the ZendeskTrigger node. Attackers who know the webhook URL can send unsigned POST requests to trigger workflows with arbitrary malicious data.

Affected products

n8n-io n8n: before 1.123.18; from 2.0.0 before 2.6.2 — fixed in 1.123.18, 2.6.2

How to fix

Upgrade to a fixed version: n8n-io n8n 1.123.18, 2.6.2. Check the vendor advisory for mitigations.

References

https://github.com/n8n-io/n8n/security/advisories/GHSA-38c7-23hj-2wgq
https://www.vulncheck.com/advisories/n8n-webhook-forgery-via-unsigned-post-requests-in-zendesktrigger

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