{"id":"CVE-2026-39974","aliases":["GHSA-4ggg-h7ph-26qr"],"url":"https://o3.security/vulnerability/CVE-2026-39974","summary":"n8n-MCP has an Authenticated SSRF via instance-URL header in multi-tenant HTTP mode","details":"n8n-MCP is a Model Context Protocol (MCP) server that provides AI assistants with comprehensive access to n8n node documentation, properties, and operations. Prior to 2.47.4, an authenticated Server-Side Request Forgery in n8n-mcp allows a caller holding a valid AUTH_TOKEN to cause the server to issue HTTP requests to arbitrary URLs supplied through multi-tenant HTTP headers. Response bodies are reflected back through JSON-RPC, so an attacker can read the contents of any URL the server can reach — including cloud instance metadata endpoints (AWS IMDS, GCP, Azure, Alibaba, Oracle), internal network services, and any other host the server process has network access to. The primary at-risk deployments are multi-tenant HTTP installations where more than one operator can present a valid AUTH_TOKEN, or where a token is shared with less-trusted clients. Single-tenant stdio deployments and HTTP deployments without multi-tenant headers are not affected. This vulnerability is fixed in 2.47.4.","published":"2026-04-09T16:45:20.490Z","modified":"2026-07-15T01:49:11.066065679Z","cvss":{"score":8.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"n8n-mcp","fixedVersion":"2.47.4"}],"fix":{"url":"https://github.com/czlonkowski/n8n-mcp/commit/d9d847f230923d96e0857ccecf3a4dedcc9b0096","label":"czlonkowski/n8n-mcp@d9d847f"},"references":[{"type":"WEB","url":"https://github.com/czlonkowski/n8n-mcp/releases/tag/v2.47.4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39974.json"},{"type":"ADVISORY","url":"https://github.com/czlonkowski/n8n-mcp/security/advisories/GHSA-4ggg-h7ph-26qr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-39974"},{"type":"FIX","url":"https://github.com/czlonkowski/n8n-mcp/commit/d9d847f230923d96e0857ccecf3a4dedcc9b0096"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T01:49:11.066065679Z"}}