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GHSA-pfm2-2mhg-8wpx
No affected components available
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.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the confidentiality of the information.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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