CVE-2026-39974 json
n8n-MCP has an Authenticated SSRF via instance-URL header in multi-tenant HTTP mode
published 2026-04-08 7 mo ago modified 2026-10-26 13 d ago also GHSA-4ggg-h7ph-26qr , EUVD-2026-20968
- cvss
- 8.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 25%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- npm n8n-mcp 2.47.4
- n8n-mcp n8n-mcp 2.47.4
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.32% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N |
| GitHub | 3.1 | 8.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | n8n-mcp | <2.47.4 |
2.47.4 |
Affected products
- czlonkowski n8n-mcp
Classification
- Weakness
-
- CWE-918 Server-Side Request Forgery
References
-
github.com
/czlonkowski/n8n-mcp/commit/d9d847f230923d96e0857ccecf3a4dedcc9b0096
web, patch
-
github.com
/czlonkowski/n8n-mcp/security/advisories/GHSA-4ggg-h7ph-26qr
web, vendor-advisory
-
github.com
/czlonkowski/n8n-mcp/releases/tag/v2.47.4
web, release-notes
-
nvd.nist.gov
/vuln/detail/CVE-2026-39974
advisory
-
github.com
/czlonkowski/n8n-mcp
package
Sources
- CVE List CVE-2026-39974
- GitHub Advisory GHSA-4ggg-h7ph-26qr
- NVD CVE-2026-39974
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