Vulnerability Database

362,176

Total vulnerabilities in the database

n8n-mcp has authenticated SSRF via instance-URL header in multi-tenant HTTP mode — n8n-mcp

Server-Side Request Forgery (SSRF)

Impact

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.

Affected versions

n8n-mcp2.47.3 (all versions up to and including 2.47.3).

Patched versions

n8n-mcp 2.47.4 and later.

Workarounds

If you cannot immediately upgrade:

  1. 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.
  2. 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.
  3. Restrict AUTH_TOKEN distribution — ensure the bearer token is only held by fully trusted operators until you can upgrade.

Remediation

Upgrade 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.

Credits

Reported by the Eresus Security Research Team. @ibrahmsql

  • Published: Apr 8, 2026
  • Updated: Apr 9, 2026
  • GHSA: GHSA-4ggg-h7ph-26qr
  • Severity: High
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Unknown
  • Score:
  • AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

CWEs:

Frequently Asked Questions

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CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

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Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

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