CVE-2026-42230 Details
Description
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.
A vulnerability in n8n's OAuth client registration process allows for open redirects to attacker-controlled URLs. The issue arises because the /mcp-oauth/register endpoint accepted registrations without authentication, permitting arbitrary redirect_uri values. When a user denies the MCP OAuth consent dialog, the handleDeny handler redirects to the registered redirect_uri without validation. This flaw can be exploited by crafting a phishing link that, when clicked, redirects the user to an external site after denying consent. The vulnerability affects n8n versions prior to 1.123.32, 2.17.4, and 2.18.1.
Users can upgrade to n8n versions 1.123.32, 2.17.4, or 2.18.1 to address this vulnerability. If an immediate upgrade is not possible, administrators should restrict network access to the n8n instance or limit access to trusted users.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 4, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/n8n-io/n8n/security/advisories/GHSA-f6x8-65q6-j9m9 | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-601 | URL Redirection to Untrusted Site ('Open Redirect') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| n8n n8n | < 1.123.32 >= 2.17.0, < 2.17.4 2.18.0 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 6, 2026 | Initial Analysis | [email protected] |
| May 4, 2026 | New CVE Received | [email protected] |