CVE-2026-21858: N8n N8n Vulnerable To Unauthenticated File Vulnerability

CRITICAL
Advisory Identifier: GHSA-v4pr-fm98-w9pg
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CVSS 10.0
CWE-20
Published
Advisory Summary

CVE-2026-21858 is a CRITICAL (CVSS 10.0) n8n vulnerable to unauthenticated file vulnerability (CWE-20: Improper Input Validation) affecting N8n libraries in the npm ecosystem. The issue involves n8n vulnerable to unauthenticated file access via improper webhook request handling. Remediation is available by upgrading affected packages to version 1.121.0.

CVE-2026-21858 at a Glance

CVE Identifier CVE-2026-21858
GHSA Identifier GHSA-v4pr-fm98-w9pg
Severity CRITICAL
CVSS v3.1 Base Score 10.0
CWE Classification CWE-20: Improper Input Validation
Affected Product N8n
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 10.0

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-21858

To remediate this vulnerability, upgrade all affected N8n dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

n8n fixed: 1.121.0 
npm install n8n@1.121.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls n8n

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-21858, inspect your project dependencies using npm:

npm ls n8n

Analyze the terminal output to locate any version of N8n in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.121.0), your application is affected.

Note: The npm ls n8n command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In N8n, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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.

CVE-2026-21858 Affected N8n Versions

1 component(s)
Fixed Versions:
1.121.0
Product / Package Ecosystem Affected Versions Fixed Version
n8n
npm/n8n
npm
≥ 1.65.0
< 1.121.0
1.121.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/n8n-io/n8n/security/advisories/GHSA-v4pr-fm98-w9pg
NVD — CVE-2026-21858 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-21858
N8n Source Repository REPOSITORY
https://github.com/n8n-io/n8n
www.cyera.com/research-labs/ni8ma... WEB
https://www.cyera.com/research-labs/ni8mare-unauthenticated-remote-code-execution-in-n8n-cve-2026-21858

Frequently Asked Questions

What is CVE-2026-21858?
CVE-2026-21858 is a security vulnerability in N8n involving n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling under CWE-20: Improper Input Validation.
Which N8n versions are affected?
Affected versions include releases prior to 1.121.0 across affected packages: n8n.
What version fixes CVE-2026-21858?
Upgrading to 1.121.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is n8n affected?
Yes, n8n is affected in releases prior to 1.121.0. Upgrade your dependency to 1.121.0 or later.
What is the CVSS score of CVE-2026-21858?
CVE-2026-21858 has a CVSS v3.1 base score of 10.0 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N.
What CWE is associated with CVE-2026-21858?
CVE-2026-21858 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check npm dependencies for CVE-2026-21858?
Run the dependency tree command: 'npm ls n8n'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-v4pr-fm98-w9pg",
  "modified" : "2026-01-13T15:04:59Z",
  "published" : "2026-01-07T19:20:19Z",
  "aliases" : [ "CVE-2026-21858" ],
  "summary" : "n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling",
  "details" : "### Impact\nA 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.\n\n### Patches\nThe issue has been fixed in n8n version 1.121.0. Users should upgrade to this version or later to remediate the vulnerability.\n\n### Workarounds\nNo official workarounds are available. As a temporary mitigation, users may restrict or disable publicly accessible webhook and form endpoints until upgrading.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "n8n"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.65.0"
      }, {
        "fixed" : "1.121.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/n8n-io/n8n/security/advisories/GHSA-v4pr-fm98-w9pg"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-21858"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/n8n-io/n8n"
  }, {
    "type" : "WEB",
    "url" : "https://www.cyera.com/research-labs/ni8mare-unauthenticated-remote-code-execution-in-n8n-cve-2026-21858"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-07T19:20:19Z",
    "nvd_published_at" : "2026-01-08T00:15:59Z"
  }
}