GHSA-56c3-vfp2-5qqj is a high-severity (CVSS 8.5) vulnerability in n8n-mcp. O3 Security confirms whether GHSA-56c3-vfp2-5qqj is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
n8n-mcp's IPv4-mapped IPv6 addresses bypass SSRF protection in validateUrlSync(), enabling full SSRF for SDK embedders
Real-World Exposure
n8n-mcpReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | n8n-mcp | ≥ 2.47.4&&< 2.47.14 | 2.47.14 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for n8n-mcp. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update n8n-mcp to 2.47.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-56c3-vfp2-5qqj is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-56c3-vfp2-5qqj is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-56c3-vfp2-5qqj. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-56c3-vfp2-5qqj in your dependencies?
O3 detects GHSA-56c3-vfp2-5qqj across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.