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Medium

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

Type: advisorySources: OSV

n8n-MCP is an MCP server that provides AI assistants access to n8n node documentation, properties, and operations. Prior to version 2.47.11, 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. This issue has been patched in version 2.47.11.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-41495
Confirmed fixed CVEs
Not specified
Updated in this feed
2 Nov 2026, 21:06 UTC · Revision 1

Source evidence

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

core-osv · Original source

Published 8 May 2026, 18:58 UTC

n8n-MCP is an MCP server that provides AI assistants access to n8n node documentation, properties, and operations. Prior to version 2.47.11, 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. This issue has been patched in version 2.47.11.

osv:CVE-2026-41495
Complete source record
{
  "id": "3bb14c276d5a626692abd23f102ea923d95791d7a0fd1b641166cc09ea31939f",
  "url": "https://osv.dev/vulnerability/CVE-2026-41495",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "n8n-MCP Logs Sensitive Request Data on Unauthorized /mcp Requests",
    "summary": "n8n-MCP is an MCP server that provides AI assistants access to n8n node documentation, properties, and operations. Prior to version 2.47.11, 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. This issue has been patched in version 2.47.11.",
    "evidence": "osv:CVE-2026-41495",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-41495",
      "aliases": [
        "CVE-2026-41495",
        "GHSA-pfm2-2mhg-8wpx"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/czlonkowski/n8n-mcp",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "ef9a8562a15f5e946112e8c63aec8acc6ac63ae3"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.47.11"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "ef9a8562a15f5e946112e8c63aec8acc6ac63ae3"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v2.47.11"
                  },
                  {
                    "cpe": "cpe:2.3:a:n8n-mcp:n8n-mcp:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.47.11"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
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            "v2.47.9",
            "v2.47.8",
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-41495.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:23.639333721Z",
      "provider": "osv",
      "references": [
        "https://github.com/czlonkowski/n8n-mcp/releases/tag/v2.47.11",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41495.json",
        "https://github.com/czlonkowski/n8n-mcp/security/advisories/GHSA-pfm2-2mhg-8wpx",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-41495"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-532"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41495.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-41495",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 490080,
  "published_at": "2026-05-08T18:58:24.574+00:00"
}