{"id":"GHSA-4ggg-h7ph-26qr","revision":"af6ad9983fd54a6188b41d49490cc13f","records":[{"revision":"af6ad9983fd54a6188b41d49490cc13f","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-4ggg-h7ph-26qr","aliases":["CVE-2026-39974"],"title":"n8n-mcp has authenticated SSRF via instance-URL header in multi-tenant HTTP mode","description":"## Impact\nAn 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.\n\nThe 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.\n\n## Affected versions\n`n8n-mcp` ≤ `2.47.3` (all versions up to and including 2.47.3).\n\n## Patched versions\n`n8n-mcp` `2.47.4` and later.\n\n## Workarounds\nIf you cannot immediately upgrade:\n1. **Egress filtering at the network layer** — block outbound traffic from the `n8n-mcp` container to RFC1918 ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16), link-local `169.254.0.0/16`, and any other internal ranges. This defends against any future SSRF-class issue and is recommended even after upgrading.\n2. **Disable multi-tenant headers** — if your deployment does not require per-request instance switching, unset `ENABLE_MULTI_TENANT` and do not accept `x-n8n-url` / `x-n8n-key` headers at the reverse proxy.\n3. **Restrict `AUTH_TOKEN` distribution** — ensure the bearer token is only held by fully trusted operators until you can upgrade.\n\n## Remediation\nUpgrade to `n8n-mcp` 2.47.4 or later. No configuration changes are required; the fix adds validation at the URL entry points and normalizes URLs at the API client layer.\n\n## Credits\nReported by the Eresus Security Research Team. @ibrahmsql","state":0,"publishedAt":"2026-04-08T19:53:48+00:00","modifiedAt":"2026-04-09T19:16:17.275218+00:00","affected":[{"ecosystem":"npm","name":"n8n-mcp","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"2.47.4"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"HIGH"}],"references":["https://github.com/czlonkowski/n8n-mcp/security/advisories/GHSA-4ggg-h7ph-26qr","https://nvd.nist.gov/vuln/detail/CVE-2026-39974","https://github.com/czlonkowski/n8n-mcp/commit/d9d847f230923d96e0857ccecf3a4dedcc9b0096","https://github.com/czlonkowski/n8n-mcp","https://github.com/czlonkowski/n8n-mcp/releases/tag/v2.47.4"],"sourceUrl":"https://github.com/advisories/GHSA-4ggg-h7ph-26qr","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-4ggg-h7ph-26qr","identifiers":["GHSA-4ggg-h7ph-26qr","CVE-2026-39974"]},"retained":false,"historicalAffected":[]}],"coverage":[]}