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N8nApplication

CVE-2026-42235

CRITICAL · 9.6 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 →
100/100
Remediation priority · Urgent
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, an unauthenticated attacker could register a malicious MCP OAuth client with a crafted client_name. If a victim user authorized the OAuth consent dialog and a second user subsequently revoked that access, a toast notification would render the injected script. Clicking the link would execute arbitrary JavaScript in the victim's authenticated n8n browser session, enabling credential and session token theft, workflow manipulation, or privilege escalation. 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

A stored XSS vulnerability in n8n allows unauthenticated attackers to inject malicious JavaScript via the OAuth client registration endpoint using a crafted client_name. When a victim authorizes the OAuth consent and another user revokes access, the toast notification renders the injected script, enabling session hijacking upon user interaction.

MitigationUpgrade to n8n versions 1.123.32, 2.17.4, or 2.18.1 which contain the patch for this 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
High
Integrity
High
Availability
High

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

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. Check installed n8n version
    Run `n8n --version` or check the version in the n8n UI footer. In Docker, inspect the container image tag or run `docker ps` and check the image.
    Affected if The installed version is less than 1.123.32, OR between 2.17.0 and 2.17.4 (exclusive), OR exactly 2.18.0
  2. Verify OAuth is enabled
    Check if OAuth 2.0 is configured in n8n by navigating to Settings > Credentials > OAuth2 or inspecting the database table `oauth2_client` if you have database access.
    Affected if OAuth is enabled and clients can be registered (the default n8n setup allows OAuth client registration)
  3. Inspect registered OAuth clients for suspicious client_name
    Query the `oauth2_client` table in the database or use the n8n API endpoint if accessible to list OAuth clients. Look for client_name values containing HTML tags, script elements, or JavaScript event handlers (onload, onerror, etc.).
    Affected if Any OAuth client exists with a client_name containing <script>, <img, onmouseover, javascript:, or other XSS vectors
  4. Review audit or access logs for unauthorized OAuth client creation
    Check n8n logs and database audit tables for entries related to OAuth client creation, particularly from unauthenticated or unexpected IP addresses.
    Affected if There are log entries showing OAuth client registration by unknown or unauthorized parties

You are affected if your n8n version falls within the vulnerable ranges AND OAuth is enabled with any suspicious OAuth clients present in the system.

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 vulnerability.

Recommended fix High confidence

Upgrade to n8n version 1.123.32 (for 1.x users), 2.17.4 (for 2.17.x users), or 2.18.1 (for 2.18.0 users) - choose the appropriate version based on your current major/minor branch

  1. 1. Identify the currently installed n8n version by checking the n8n instance or Docker container
  2. 2. If running version 1.x.x and less than 1.123.32: Plan upgrade to version 1.123.32 or later
  3. 3. If running version 2.17.0 through 2.17.3: Plan upgrade to version 2.17.4 or later
  4. 4. If running version 2.18.0: Plan upgrade to version 2.18.1 or later
  5. 5. Before upgrading in production, review the n8n release notes for the target version for any breaking changes
  6. 6. Back up the n8n database and configuration
  7. 7. Perform the upgrade following n8n's standard upgrade procedure (e.g., Docker pull, npm update, or helm upgrade depending on deployment method)
  8. 8. Verify the upgrade was successful by checking the n8n version after restart
Caveat No breaking changes documented in the provided vulnerability description; check release notes for specific versions

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

Fix this in N8n Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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-2026-42235 in production — separate from our analysis above.

No notes yet

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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