Main Vulnerability Database Vulnerabilities #VU121066

Arbitrary file upload in n8n - CVE-2026-21877

Published: January 7, 2026 / Updated: January 9, 2026

Vulnerability identifier: #VU121066

CSH Severity: Medium

CVSS v4: 8.7 [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]

CVE-ID: CVE-2026-21877

CWE-ID: CWE-434

Exploitation vector: Remote access

Exploit availability: Public exploit is available

Vulnerability details

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.

Affected software

n8n

How to mitigate CVE-2026-21877

Install updates from vendor's website.

n8n - update to 1.121.3

Links to Public Exploits and PoC-codes

Exploit #12290 - LAB-CVES (Welcome to LAB-CVE, a curated collection of containerized, ready-to-launch labs designed for security researchers, pentesters, and students. This repository provides safe, isolated environments to reproduce, exploit, and mitigate real-world (and (January 9, 2026)

External References

https://github.com/n8n-io/n8n/security/advisories/GHSA-v364-rw7m-3263

Related Security Bulletins

Arbitrary file upload in n8n