CVE-2026-42449

High

Published: 07 May 2026

Published

07 May 2026

Modified

14 May 2026

KEV Added

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Patch

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CVSS Score v3.1 8.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

EPSS Score 0.0021 10.8th percentile

Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-42449 is a high-severity SSRF (CWE-918) vulnerability in N8N-Mcp N8N-Mcp. Its CVSS base score is 8.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 10.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as AI Agent Protocols and Integrations; in the Protocol-Specific Risks risk domain.

OWASP Top 10 for Web (2025)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-28442

Vulnerability details

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.

CWE(s): CWE-918

AI Security AnalysisAI

AI Category: AI Agent Protocols and Integrations
Risk Domain: Protocol-Specific Risks
OWASP Top 10 for LLMs 2025: None mapped
Classification Reason: Matched keywords: ai, mcp

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1552.005 Cloud Instance Metadata API Credential Access

Adversaries may attempt to access the Cloud Instance Metadata API to collect credentials and other sensitive data.

attack.mitre.org →

Why these techniques?

SSRF vuln (CWE-918) directly enables exploitation of public-facing n8n-MCP server (T1190) to reach cloud metadata endpoints and exfil credentials (T1552.005).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0