Improper access control in n8n - #VU139109
Published: July 22, 2026
Vulnerability identifier: #VU139109
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: N/A
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: n8n
Affected software:
n8n
n8n
Detailed vulnerability description
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to improper access control in the VM expression engine sandbox when creating or editing a workflow expression that uses array-element access. A remote user can obtain a reference to a host built-in and pollute its prototype to cause a denial of service.
Only instances running the VM expression engine are vulnerable.
Remediation
Install security update from vendor's website.