CVE-2026-42230: CWE-601: URL Redirection to Untrusted Site ('Open Redirect') in n8n-io n8n
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.
AI Analysis
Technical Summary
The vulnerability in n8n versions before 1.123.32, 2.17.4, and 2.18.1 involves the /mcp-oauth/register endpoint accepting OAuth client registrations without authentication, allowing arbitrary redirect_uri parameters. If a user denies consent on the MCP OAuth dialog, the handleDeny handler redirects to the registered redirect_uri without validation, enabling an open redirect attack. This can be exploited by attackers to craft phishing links that redirect users to attacker-controlled sites upon denial of consent. The issue has been fixed in the stated versions.
Potential Impact
This vulnerability allows attackers to perform open redirect attacks by redirecting users to attacker-controlled URLs after they deny the OAuth consent dialog. This can facilitate phishing attacks by misleading users into visiting malicious sites. The CVSS 4.0 score is 5.1 (medium severity), indicating a moderate risk without requiring privileges or user interaction beyond clicking 'Deny'.
Mitigation Recommendations
A fix is available in n8n versions 1.123.32, 2.17.4, and 2.18.1. Users should upgrade to these or later versions to remediate the vulnerability. No vendor advisory content contradicts this; therefore, upgrading is the recommended mitigation.
CVE-2026-42230: CWE-601: URL Redirection to Untrusted Site ('Open Redirect') in n8n-io n8n
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in n8n versions before 1.123.32, 2.17.4, and 2.18.1 involves the /mcp-oauth/register endpoint accepting OAuth client registrations without authentication, allowing arbitrary redirect_uri parameters. If a user denies consent on the MCP OAuth dialog, the handleDeny handler redirects to the registered redirect_uri without validation, enabling an open redirect attack. This can be exploited by attackers to craft phishing links that redirect users to attacker-controlled sites upon denial of consent. The issue has been fixed in the stated versions.
Potential Impact
This vulnerability allows attackers to perform open redirect attacks by redirecting users to attacker-controlled URLs after they deny the OAuth consent dialog. This can facilitate phishing attacks by misleading users into visiting malicious sites. The CVSS 4.0 score is 5.1 (medium severity), indicating a moderate risk without requiring privileges or user interaction beyond clicking 'Deny'.
Mitigation Recommendations
A fix is available in n8n versions 1.123.32, 2.17.4, and 2.18.1. Users should upgrade to these or later versions to remediate the vulnerability. No vendor advisory content contradicts this; therefore, upgrading is the recommended mitigation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-25T05:37:12.117Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69f8eaaecbff5d8610415af9
Added to database: 5/4/2026, 6:51:26 PM
Last enriched: 5/4/2026, 7:07:05 PM
Last updated: 5/4/2026, 9:15:11 PM
Views: 5
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