n8n-MCP: Multi-tenant MCP requests fall back to process-level n8n credentials when tenant headers are absent or incomplete

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.1 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

EPSS

• CVE-2026-45707: 0.24% estimated exploitation activity in the next 30 days; percentile 14.59 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary When ENABLEMULTITENANT=true, the HTTP transport documents that the target n8n instance is selected per-request from x-n8n-url / x-n8n-key headers. Requests that omitted those headers — or supplied only one of them — silently fell back to the process-level N8NAPIURL / N8NAPIKEY credentials configured for the operator's own n8n instance. As a result, an authenticated MCP tenant could cause n8n management calls to execute against the operator's instance instead of its own. This affects HTTP-mode deployments of n8n-mcp that are run as a shared multi-tenant service. Single-tenant deployments (ENABLEMULTITENANT unset or false) are not affected. Impact An authenticated MCP tenant exploiting this path could read and write workflows, executions, data-table contents, and credential metadata on the operator's n8n instance. If the operator's n8n permits Code-node execution that reaches OS-level modules, the path could escalate to remote code execution inside the operator's n8n runtime.…

Published by the source

18 May 2026, 17:41 UTC

Last modified by the source

9 Jun 2026, 10:45 UTC

Source last checked

26 Oct 2026, 12:53 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-jxx9-px88-pj69

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-jxx9-px88-pj69

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# Patch Next advisory brief: CVE-2026-45707

Advisory: n8n-MCP: Multi-tenant MCP requests fall back to process-level n8n credentials when tenant headers are absent or incomplete
IDs: CVE-2026-45707, GHSA-jxx9-px88-pj69
Record: https://patchnext.com/advisories/cve-2026-45707 (revision 2, source checked 26 Oct 2026, 12:53 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: n8n-mcp 2.51.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm n8n-mcp: affected <= 2.51.1; fixed in 2.51.2

## Suggested inspection (read-only)
- `npm ls n8n-mcp --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on n8n-mcp.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-jxx9-px88-pj69 (OSV record GHSA-jxx9-px88-pj69 lists affected ranges: npm n8n-mcp >=0 <2.51.2 (fixed))
- Verified: https://github.com/advisories/GHSA-jxx9-px88-pj69 (GitHub-reviewed advisory GHSA-jxx9-px88-pj69 lists affected ranges: npm n8n-mcp >=0 <=2.51.1)

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