Arbitrary file upload in n8n - CVE-2026-21877
Published: January 7, 2026 / Updated: January 9, 2026
Vulnerability identifier: #VU121066
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Green
CVE-ID: CVE-2026-21877
CWE-ID: CWE-434
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vendor: n8n
Affected software:
n8n
n8n
Detailed vulnerability description
The vulnerability allows a remote user to compromise vulnerable system.
The vulnerability exists due to insufficient validation of file during file upload. A remote user can upload a malicious file and execute it on the server.
How to mitigate CVE-2026-21877
Install updates from vendor's website.