What’s Vulnerable › Vulnerabilities
CVE-2026-42230: n8n: Open Redirect in MCP OAuth Consent Flow
- Severity: medium (CVSS 6.1 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-05-04 · updated 2026-06-17
- Weakness: CWE-601
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.
Affected products
- n8n-io n8n: before 1.123.32; from 2.17.0 before 2.17.4; 2.18.0 — fixed in 1.123.32, 2.17.4
How to fix
Upgrade to a fixed version: n8n-io n8n 1.123.32, 2.17.4. Check the vendor advisory for mitigations.
References
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