Server-Side Request Forgery in n8n-MCP Server Exposing Sensitive Data
CVE-2026-39974

8.5HIGH

Key Information:

Vendor: Czlonkowski
Status: N8n-mcp
Vendor: CVE Published:; 9 April 2026

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What is CVE-2026-39974?

The n8n-MCP server, prior to version 2.47.4, is vulnerable to a Server-Side Request Forgery (SSRF) which allows authenticated users with a valid AUTH_TOKEN to send HTTP requests to arbitrary URLs specified in multi-tenant HTTP headers. The server reflects the responses back through JSON-RPC, enabling attackers to access sensitive data from any reachable URL, including cloud metadata endpoints and internal network services. This vulnerability poses significant risks in multi-tenant environments where multiple operators can present valid AUTH_TOKENS. The flaw has been addressed in the 2.47.4 release.