Docker CVE-2026-42449
HIGH
GHSA-56c3-vfp2-5qqj
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
Lifecycle Timeline
5DescriptionNVD
Impact
In the SDK embedder path (N8NDocumentationMCPServer constructor, getN8nApiClient(), and validateInstanceContext()), the synchronous URL validator in SSRFProtection.validateUrlSync() had no IPv6 checks. IPv4-mapped IPv6 addresses such as http://[::ffff:169.254.169.254] bypassed the cloud-metadata, localhost, and private-IP range checks. An attacker able to supply an n8nApiUrl value could cause the server to issue HTTP requests to cloud metadata endpoints (AWS IMDS, GCP, Azure, Alibaba, Oracle), RFC1918 private networks, or localhost services. Response bodies are returned to the caller (non-blind SSRF), and the n8nApiKey is forwarded in the x-n8n-api-key header to the attacker-controlled target.
The first-party HTTP server deployment was not primarily affected - it has a second async validator (validateWebhookUrl) that catches IPv6 addresses.
Impact category: CWE-918 (Server-Side Request Forgery).
Affected
Deployments embedding n8n-mcp as an SDK using N8NDocumentationMCPServer or N8NMCPEngine with user-supplied InstanceContext on versions v2.47.4 through v2.47.13.
Patched
v2.47.14 and later.
- npm:
npx n8n-mcp@latest(or pin to>= 2.47.14) - Docker:
docker pull ghcr.io/czlonkowski/n8n-mcp:latest
Workarounds
If developers cannot upgrade immediately:
- Validate URLs before passing to the SDK - reject any
n8nApiUrlwhose hostname is an IP literal (bracketed IPv6 or dotted IPv4) before callingN8NDocumentationMCPServer/getN8nApiClient(). Accept only URLs with DNS-resolvable hostnames. - Restrict egress at the network layer - block outbound traffic from the n8n-mcp process 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 cloud metadata endpoints. Defense-in-depth against this class of issue and recommended even after upgrading. - Do not accept user-controlled
n8nApiUrlvalues - if the project's integration derives the URL from internal configuration only, this vulnerability is not reachable.
Upgrading to v2.47.14 is still strongly recommended.
Credit
Reported by @manthanghasadiya.
AnalysisAI
Server-Side Request Forgery (SSRF) in n8n-mcp SDK allows authenticated remote attackers to access cloud metadata endpoints and internal network resources via IPv4-mapped IPv6 address bypass. Versions 2.47.4 through 2.47.13 fail to validate IPv6 addresses in the synchronous URL validator (SSRFProtection.validateUrlSync()), enabling attackers who control the n8nApiUrl parameter to bypass RFC1918, localhost, and cloud metadata protections using addresses like [::ffff:169.254.169.254]. …
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RemediationAI
Within 24 hours: Identify all instances of n8n-mcp SDK versions 2.47.4 through 2.47.13 in your environment using software inventory tools and dependency scanners. Within 7 days: Upgrade all affected instances to version 2.47.14 or later; prioritize production and cloud-connected deployments. …
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