n8n: Open Redirect in MCP OAuth Consent Flow
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Active
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Spoofing
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-601.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| n8n | n8n | before 1.123.32; 2.17.0 to before 2.17.4; 2.18.0 to before 2.18.1 | 1.123.32, 2.17.4, 2.18.1 | Patch available | CNA |
| — | n8n (npm) | before 1.123.32 | 1.123.32 | Patch available | GHSA-f6x8-65q6-j9m9 |
| — | n8n (npm) | 2.18.0 to before 2.18.1 | 2.18.1 | Patch available | GHSA-f6x8-65q6-j9m9 |
| — | n8n (npm) | 2.0.0 to before 2.17.4 | 2.17.4 | Patch available | GHSA-f6x8-65q6-j9m9 |
- n8n Vendorn8n Affected before 1.123.32; 2.17.0 to before 2.17.4; 2.18.0 to before 2.18.1 Fixed in 1.123.32, 2.17.4, 2.18.1 Patch available CNA
- n8n (npm) Vendor— Affected before 1.123.32 Fixed in 1.123.32 Patch available GHSA-f6x8-65q6-j9m9
- n8n (npm) Vendor— Affected 2.18.0 to before 2.18.1 Fixed in 2.18.1 Patch available GHSA-f6x8-65q6-j9m9
- n8n (npm) Vendor— Affected 2.0.0 to before 2.17.4 Fixed in 2.17.4 Patch available GHSA-f6x8-65q6-j9m9
Remediation
- Fix · CNA n8n (n8n-io) Fixed in 1.123.32, 2.17.4, 2.18.1
- Fix · GHSA-f6x8-65q6-j9m9 n8n (npm) Fixed in 1.123.32 Advisory →
- Fix · GHSA-f6x8-65q6-j9m9 n8n (npm) Fixed in 2.18.1 Advisory →
- Fix · GHSA-f6x8-65q6-j9m9 n8n (npm) Fixed in 2.17.4 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-42230
- 2026-10-03 Alias added: GHSA-f6x8-65q6-j9m9
References
More N8n vulnerabilities
- TI-2025-42131 n8n Vulnerable to Remote Code Execution via Expression Injection KEVCVSS 3.1CRITICAL 10.0
- TI-2026-17560 n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling CVSS 3.1CRITICAL 10.0
- TI-2026-01167 Authenticated users can bypass the Expression sandbox mechanism to achieve full remote… CVSS 3.1CRITICAL 9.9
- TI-2026-00644 Sandbox escape in n8n Python task runner allows for arbitrary code execution on the underlying host. CVSS 3.1CRITICAL 9.9
- TI-2025-35293 An arbitrary file upload vulnerability in the Chat Trigger component of N8N v1.95.3… CVSS 3.1HIGH 8.8
- TI-2023-12275 The n8n package 0.218.0 for Node.js allows Escalation of Privileges. CVSS 3.1HIGH 8.8
Sources
- CVE-2026-42230 · CVE Program
- CVE-2026-42230 · NVD
- FIRST EPSS
- GHSA-f6x8-65q6-j9m9 · GitHub Advisory Database · CC BY 4.0
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