Improper Validation of Specified Type of Input Affecting n8n package, versions >=1.65.0 <1.121.0
Threat Intelligence
This vulnerability is trending on Twitter; this may indicate a growing threat.
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-JS-N8N-14900573
- published8 Jan 2026
- disclosed7 Jan 2026
- creditDor Attias
Introduced: 7 Jan 2026
CVE-2026-21858 (opens in a new tab)How to fix?
Upgrade n8n to version 1.121.0 or higher.
Overview
n8n is a n8n Workflow Automation Tool
Affected versions of this package are vulnerable to Improper Validation of Specified Type of Input that is passed to the handleFormData() function. An attacker can gain unauthorized access to files on the underlying server by requests with unexpected content-type values to exposed endpoints. This allows the attacker to make arbitrary file contents available via the chat interface. Sensitive cookie values retrieved can then be used to bypass authentication and further compromise of the application and underlying system.
Note:
For users using the main n8n package it is recommended to upgrade to n8n@1.121.0.
##Workaround This vulnerability can be mitigated by restricting or disabling publicly accessible webhook and form endpoints.