CVE-2026-42449

May 7, 2026, 9:16 p.m.

8.5
High

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.

Product(s) Impacted

Vendor Product Versions
N8n
  • N8n
  • *

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-918
Server-Side Request Forgery (SSRF)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
a n8n n8n / 2.47.4-2.47.13 / / / / / /

References

https://github.com/czlonkowski/n8n-mcp/commit/9639f757853149f0cb16663cc8b6b6468f27a25f
https://github.com/czlonkowski/n8n-mcp/security/advisories/GHSA-56c3-vfp2-5qqj

Tags

[email protected]
CWE-918
2026-05-07
CVE-2026-42449

CVSS Score

8.5 / 10

CVSS Data - 3.1

  • Attack Vector: NETWORK
  • Attack Complexity: LOW
  • Privileges Required: LOW
  • Scope: CHANGED
  • Confidentiality Impact: HIGH
  • Integrity Impact: LOW
  • Availability Impact: NONE

    • CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

    View Vector String

Timeline

Published: May 7, 2026, 9:16 p.m.
Last Modified: May 7, 2026, 9:16 p.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.