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N8nApplication

CVE-2026-42230

MEDIUM · 6.1 CVSS v3.1 Published 2026-05-04
Fix available
A fix is available. Upgrade to 1.123.32 / 2.17.4 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the /mcp-oauth/register endpoint accepted OAuth client registrations without authentication, allowing arbitrary redirect_uri values to be registered. When a user denies the MCP OAuth consent dialog, the handleDeny handler redirects the user to the registered redirect_uri without validation, enabling an open redirect to an attacker-controlled URL. An attacker can craft a phishing link and send it to a victim; if the victim clicks "Deny" on the consent page, they are silently redirected to an external site. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The n8n workflow automation platform's /mcp-oauth/register endpoint accepts unauthenticated OAuth client registrations and allows arbitrary redirect_uri values. The handleDeny handler then redirects users to this attacker-controlled URI when they deny consent, enabling open redirect attacks for phishing.

MitigationUpgrade to n8n versions 1.123.32, 2.17.4, or 2.18.1 which contain the patch for this open redirect vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
N8nApplication
Affected:< 1.123.32>= 2.17.0, < 2.17.4= 2.18.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine your installed n8n version
    Run 'n8n --version' from the command line, check your package.json file, or identify your Docker image tag to find the exact version number
    Affected if The version is less than 1.123.32, between 2.17.0 and 2.17.3 inclusive, or exactly 2.18.0
  2. Verify if MCP OAuth functionality is enabled
    Check your n8n configuration files or environment variables for MCP_OAUTH settings, or look for the /mcp-oauth/register endpoint being accessible on your instance
    Affected if MCP OAuth is enabled and the /mcp-oauth/register endpoint is exposed to unauthenticated users
  3. Test if arbitrary redirect_uri values are accepted
    Send a POST request to /mcp-oauth/register with a redirect_uri parameter pointing to an external domain you control, observing if the registration succeeds without validation
    Affected if The endpoint accepts and stores a redirect_uri pointing to an untrusted domain without rejecting or validating it
  4. Verify handleDeny handler redirect behavior
    After registering a client with an arbitrary redirect_uri, attempt to deny consent and observe if the handler redirects to the attacker-controlled URI
    Affected if The handleDeny handler redirects to the registered redirect_uri instead of a safe internal page or blocking the redirect entirely

You are affected if your n8n version falls within the vulnerable ranges AND the MCP OAuth feature is enabled with the /mcp-oauth/register endpoint exposed to unauthenticated users.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.123.32 / 2.17.4 or later
Fixed in 1.123.322.17.4
Interim mitigation

Upgrade to n8n versions 1.123.32, 2.17.4, or 2.18.1 which contain the patch for this open redirect vulnerability.

Recommended fix High confidence

1.123.32 (for 1.x users), 2.17.4 (for 2.17.x users), or 2.18.1 (for 2.18.0 users)

  1. 1. Identify the current n8n version by checking the n8n UI (bottom left corner) or running `docker ps` to see the container image tag
  2. 2. If running a version in the 1.x line: Upgrade to version 1.123.32 or later
  3. 3. If running a version in the 2.17.x line: Upgrade to version 2.17.4 or later
  4. 4. If running version 2.18.0: Upgrade to version 2.18.1 or later
  5. 5. After upgrade, verify the /mcp-oauth/register endpoint now properly validates redirect_uri values
  6. 6. Test the OAuth consent flow by attempting to register a client and verify the redirect behavior on both Allow and Deny actions

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in N8n Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-42230 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data