GHSA-pfm2-2mhg-8wpx
MEDIUMGHSA-pfm2-2mhg-8wpx is a medium-severity (CVSS 5.3) vulnerability in n8n-mcp. O3 Security confirms whether GHSA-pfm2-2mhg-8wpx is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
n8n-MCP Logs Sensitive Request Data on Unauthorized /mcp Requests
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
n8n-mcpnpmDescription
Impact
When n8n-mcp runs in HTTP transport mode, incoming requests to the POST /mcp endpoint had their request metadata written to server logs regardless of the authentication outcome. In deployments where logs are collected, forwarded to external systems, or viewable outside the request trust boundary (shared log storage, SIEM pipelines, support/ops access), this can result in disclosure of:
- bearer tokens from the
Authorizationheader - per-tenant API keys from the
x-n8n-keyheader in multi-tenant setups - JSON-RPC request payloads sent to the MCP endpoint
Access control itself was not bypassed — unauthenticated requests were correctly rejected with 401 Unauthorized — but sensitive values from those rejected requests could still be persisted in logs.
Impact category: CWE-532 (Insertion of Sensitive Information into Log File).
Affected
Deployments running n8n-mcp v2.47.10 or earlier in HTTP transport mode (MCP_MODE=http). The stdio transport is not affected.
Patched
v2.47.11 and later.
- npm:
npx n8n-mcp@latest(or pin to>= 2.47.11) - Docker:
docker pull ghcr.io/czlonkowski/n8n-mcp:latest
Workarounds
If users cannot upgrade immediately:
- Restrict network access to the HTTP port (firewall, reverse proxy, or VPN) so only trusted clients can reach the endpoint.
- Switch to stdio transport (
MCP_MODE=stdio, the default for CLI invocation), which has no HTTP surface.
Credit
n8n-MCP thanks @S4nso (Organization / Jormungandr) for reporting this issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | n8n-mcp | all versions | 2.47.11 |
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 2.47.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pfm2-2mhg-8wpx 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-pfm2-2mhg-8wpx 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-pfm2-2mhg-8wpx. 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-pfm2-2mhg-8wpx in your dependencies?
O3 detects GHSA-pfm2-2mhg-8wpx across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.