🛡️ CVE-2026-41495 — n8n-mcp

🟡 CVSS 5.3 — Medium ✅ No Known Exploit CWE-532 NVD
5.3
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

n8n-MCP Logs Sensitive Request Data on Unauthorized /mcp Requests

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 Authorization header
  • per-tenant API keys from the x-n8n-key header 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](https://github.com/S4nso) (Organization / Jormungandr) for reporting this issue.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity none, availability none.

Weakness class

CVE-2026-41495 is classified as CWE-532: Insertion of Sensitive Information into Log File. Sensitive values are written to logs, which are typically kept longer and read more widely than the data warrants.

Affected software

CVE-2026-41495 is recorded against 2 packages.

  • n8n-mcp
  • unknown

Timeline and source

Published on 23 April 2026 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com (Web)
nvd.nist.gov (Advisory)
github.com (Package)
github.com (Web)

Details

Severity MEDIUM
CVSS Score 5.3
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CWE CWE-532
Public Exploit ✅ No
Source NVD
Published 2026-04-23
Updated 2026-08-12
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
n8n-mcp — —
unknown — —

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