n8n has Webhook Forgery on Zendesk Trigger Node

Impact

An attacker who knows the webhook URL of a workflow using the ZendeskTrigger node could send unsigned POST requests and trigger the workflow with arbitrary data. The node does not verify the HMAC-SHA256 signature that Zendesk attaches to every outbound webhook, allowing any party to inject crafted payloads into the connected workflow.

Patches

The issue has been fixed in n8n versions 2.6.2 and 1.123.18. Users should upgrade to one of these versions or later to remediate the vulnerability.

Workarounds

If upgrading is not immediately possible, administrators should consider the following temporary mitigations:

• Limit workflow creation and editing permissions to fully trusted users only.
• Restrict network access to the n8n webhook endpoint to known Zendesk IP ranges.

These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.