---
title: "CVE-2026-21858: n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling"
url: https://erroneo.us/security/cve/CVE-2026-21858/
description: "CVE-2026-21858 (n8n (npm)): n8n is an open source workflow automation platform. Versions starting with 1.65.0 and below 1.121.0 enable an attacker to access…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-01-07
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-21858"
kev: false
cvss: 10
epss: 0.78188
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-21858: n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling

**Signal:** High exploit likelihood. EPSS ranks it in the top 5% of all CVEs for likely exploitation in the next 30 days. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 78.2% , percentile 99.6: FIRST’s model estimates a 78.2% chance of exploitation activity in the next 30 days, higher than 99.6% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes n8n (npm) >= 1.65.0, < 1.121.0, fixed in 1.121.0 . Check your lockfile, including transitive dependencies.
- Editorial verdict: Act now. Ni8mare: n8n Unauthenticated Takeover, Plus a KEV RCE — If you self-host n8n and anything about it is reachable from the internet, upgrade today: one bug lets strangers in through public forms, and its companion RCE is on CISA's exploited list.

## What it is

n8n is an open source workflow automation platform. Versions starting with 1.65.0 and below 1.121.0 enable an attacker to access files on the underlying server through execution of certain form-based workflows. A vulnerable workflow could grant access to an unauthenticated remote attacker, resulting in exposure of sensitive information stored on the system and may enable further compromise depending on deployment configuration and workflow usage. This issue is fixed in version 1.121.0.

## Affected packages

- npm `n8n` >= 1.65.0, < 1.121.0 → fixed: 1.121.0

## Affected products (CVE record)

- n8n-io n8n: >= 1.65.0, < 1.121.0

## Severity

- GitHub_M CVSS 3.1: 10 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N`
- GitHub CVSS 3.1: 10.0 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 78.19% probability of exploitation activity in the next 30 days; percentile 99.6.

## Sources

- [GitHub Advisory GHSA-v4pr-fm98-w9pg](https://github.com/advisories/GHSA-v4pr-fm98-w9pg)
- [CVE.org record CVE-2026-21858](https://www.cve.org/CVERecord?id=CVE-2026-21858)
- [NVD entry CVE-2026-21858](https://nvd.nist.gov/vuln/detail/CVE-2026-21858)
- [github.com](https://github.com/n8n-io/n8n/security/advisories/GHSA-v4pr-fm98-w9pg)
- [cyera.com](https://www.cyera.com/research-labs/ni8mare-unauthenticated-remote-code-execution-in-n8n-cve-2026-21858)

---
Source page: https://erroneo.us/security/cve/CVE-2026-21858/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt