CVE-2026-56357: n8n Webhook Forgery On Github Webhook Vulnerability

MODERATE
Advisory Identifier: GHSA-mqpr-49jj-32rc
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CVSS 4.0
CWE-290
Published
Advisory Summary

CVE-2026-56357 is a MODERATE (CVSS 4.0) webhook forgery on github webhook vulnerability (CWE-290: Authentication Bypass by Spoofing) affecting n8n libraries in the npm ecosystem. The issue involves webhook forgery on github webhook trigger. Remediation is available by upgrading affected packages to version 1.123.15, 2.5.0.

CVE-2026-56357 at a Glance

CVE Identifier CVE-2026-56357
GHSA Identifier GHSA-mqpr-49jj-32rc
Severity MODERATE
CVSS v3.1 Base Score 4.0
CWE Classification CWE-290: Authentication Bypass by Spoofing
Affected Product n8n
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 4.0

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

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

How to Fix CVE-2026-56357

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: 1.123.15 
npm install n8n@1.123.15
n8n fixed: 2.5.0 
npm install n8n@2.5.0
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-2026-56357, 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 1.123.15), 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-290: Authentication Bypass by Spoofing, where this attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. 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 An attacker who knows the webhook URL of a workflow using the GitHub Webhook Trigger node could send unsigned POST requests and trigger the workflow with arbitrary data. The node did not implement the HMAC-SHA256 signature verification that GitHub provides to authenticate webhook deliveries, allowing any party to spoof GitHub webhook events. ## Patches The issue has been fixed in n8n versions 2.5.0 and 1.123.15. Users should upgrade to one of these versions or later to remediate the vulnerability. ## Workarounds If upgrading is not immediately possible, administrators should consider the following temporary mitigations: - Limit workflow creation and editing permissions to fully trusted users only. - Restrict network access to the n8n webhook endpoint to known GitHub webhook IP ranges. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.

CVE-2026-56357 Affected n8n Versions

2 component(s)
Fixed Versions:
1.123.152.5.0
Product / Package Ecosystem Affected Versions Fixed Version
n8n
npm/n8n
npm
< 1.123.15
1.123.15
n8n
npm/n8n
npm
≥ 2.0.0
< 2.5.0
2.5.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/n8n-io/n8n/security/advisories/GHSA-mqpr-49jj-32rc
NVD — CVE-2026-56357 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-56357
Security Fix Commit FIX COMMIT
https://github.com/n8n-io/n8n/commit/a19347a6bc9a96d5065ac77d25a811e46178c578
Security Fix Commit FIX COMMIT
https://github.com/n8n-io/n8n/commit/afe322325502f448b33bff1db1575e4447c28a36
n8n Source Repository REPOSITORY
https://github.com/n8n-io/n8n
www.vulncheck.com/advisories/n8n-webh... WEB
https://www.vulncheck.com/advisories/n8n-webhook-forgery-via-missing-hmac-sha256-signature-verification-in-github-webhook-trigger

Frequently Asked Questions

What is CVE-2026-56357?
CVE-2026-56357 is a security vulnerability in n8n involving Webhook Forgery on Github Webhook Trigger under CWE-290: Authentication Bypass by Spoofing.
Which n8n versions are affected?
Affected versions include releases prior to 1.123.15, 2.5.0 across affected packages: n8n.
What version fixes CVE-2026-56357?
Upgrading to 1.123.15, 2.5.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is n8n affected?
Yes, n8n is affected in releases prior to 1.123.15, 2.5.0. Upgrade your dependency to 1.123.15, 2.5.0 or later.
What is the CVSS score of CVE-2026-56357?
CVE-2026-56357 has a CVSS v3.1 base score of 4.0 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N.
What CWE is associated with CVE-2026-56357?
CVE-2026-56357 is classified under CWE-290: Authentication Bypass by Spoofing (This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.).
How can I check npm dependencies for CVE-2026-56357?
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-mqpr-49jj-32rc",
  "modified" : "2026-07-18T17:29:01Z",
  "published" : "2026-02-26T15:58:34Z",
  "aliases" : [ "CVE-2026-56357" ],
  "summary" : "n8n: Webhook Forgery on Github Webhook Trigger",
  "details" : "## Impact\nAn attacker who knows the webhook URL of a workflow using the GitHub Webhook Trigger node could send unsigned POST requests and trigger the workflow with arbitrary data. The node did not implement the HMAC-SHA256 signature verification that GitHub provides to authenticate webhook deliveries, allowing any party to spoof GitHub webhook events.\n\n## Patches\nThe issue has been fixed in n8n versions 2.5.0 and 1.123.15. Users should upgrade to one of these versions or later to remediate the vulnerability.\n\n## Workarounds\nIf upgrading is not immediately possible, administrators should consider the following temporary mitigations:\n- Limit workflow creation and editing permissions to fully trusted users only.\n- Restrict network access to the n8n webhook endpoint to known GitHub webhook IP ranges.\n\nThese workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "n8n"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.123.15"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "n8n"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0"
      }, {
        "fixed" : "2.5.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/n8n-io/n8n/security/advisories/GHSA-mqpr-49jj-32rc"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-56357"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/n8n-io/n8n/commit/a19347a6bc9a96d5065ac77d25a811e46178c578"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/n8n-io/n8n/commit/afe322325502f448b33bff1db1575e4447c28a36"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/n8n-io/n8n"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/n8n-webhook-forgery-via-missing-hmac-sha256-signature-verification-in-github-webhook-trigger"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-290" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-26T15:58:34Z",
    "nvd_published_at" : "2026-06-22T22:16:52Z"
  }
}