n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

10.0 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

EPSS

• CVE-2026-21858: 78.19% estimated exploitation activity in the next 30 days; percentile 99.58 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact A vulnerability in n8n allows 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. This could result in exposure of sensitive information stored on the system and may enable further compromise depending on deployment configuration and workflow usage. Patches The issue has been fixed in n8n version 1.121.0. Users should upgrade to this version or later to remediate the vulnerability. Workarounds No official workarounds are available. As a temporary mitigation, users may restrict or disable publicly accessible webhook and form endpoints until upgrading.

Published by the source

7 Jan 2026, 19:20 UTC

Last modified by the source

3 Feb 2026, 03:01 UTC

Source last checked

26 Oct 2026, 12:41 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-v4pr-fm98-w9pg

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-v4pr-fm98-w9pg

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-v4pr-fm98-w9pg

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# Patch Next advisory brief: CVE-2026-21858

Advisory: n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling
IDs: CVE-2026-21858, GHSA-v4pr-fm98-w9pg
Record: https://patchnext.com/advisories/cve-2026-21858 (revision 3, source checked 26 Oct 2026, 12:41 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 10.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: n8n 1.121.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm n8n: affected >= 1.65.0, < 1.121.0; fixed in 1.121.0

## Suggested inspection (read-only)
- `npm ls n8n --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on n8n.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-v4pr-fm98-w9pg (GitHub-reviewed advisory GHSA-v4pr-fm98-w9pg lists affected ranges: npm n8n >=1.65.0 <1.121.0)
- Verified: https://osv.dev/vulnerability/GHSA-v4pr-fm98-w9pg (OSV record GHSA-v4pr-fm98-w9pg lists affected ranges: npm n8n >=1.65.0 <1.121.0 (fixed))

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