Threaticon
Toggle sidebar

You're viewing a limited, public preview. Log in for full access.

Log in User Guide
Log in Get started
Vulnerabilities CVE-2026-42449

CVE-2026-42449

High
Open
TLP:CLEAR

n8n-MCP: IPv4-mapped IPv6 addresses bypass SSRF protection in validateUrlSync(), enabling full SSRF for SDK embedders

NVD CVE.org
Critical Infrastructure

AI Analysis

No AI analysis yet.

Description

n8n-MCP is an MCP server that provides AI assistants access to n8n node documentation, properties, and operations. In versions 2.47.4 through 2.47.13, the SDK embedder path (N8NDocumentationMCPServer constructor, getN8nApiClient(), and validateInstanceContext()), the synchronous URL validator in SSRFProtection.validateUrlSync() had no IPv6 checks. IPv4-mapped IPv6 addresses such as http://[::ffff:169.254.169.254] bypassed the cloud-metadata, localhost, and private-IP range checks. An attacker able to supply an n8nApiUrl value could cause the server to issue HTTP requests to cloud metadata endpoints, RFC1918 private networks, or localhost services. Response bodies are returned to the caller (non-blind SSRF), and the n8nApiKey is forwarded in the x-n8n-api-key header to the attacker-controlled target. Projects with deployments embedding n8n-mcp as an SDK using N8NDocumentationMCPServer or N8NMCPEngine with user-supplied InstanceContext are affected. The first-party HTTP server deployment was not primarily affected — it has a second async validator (validateWebhookUrl) that catches IPv6 addresses. This issue has been fixed in version 2.47.14. If users are unable to upgrade immediately as a workaround they can validate URLs before passing to the SDK, restrict egress at the network layer, and reject user-controlled n8nApiUrl values.

Details

CVSS Score
8.5
EPSS Score
0.21%

10.9th percentile

CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
Confidence
90%
Published
May 7, 2026
Last Modified
May 8, 2026
No notes yet. Click "Add Note" to create the first analysis note.
No opinions yet. Be the first to assess this intelligence.
Leaving Threaticon

This link opens an external site that isn't part of the platform.