n8n-MCP: Incorrect authorization can expose default-scope workflow version backups in multi-tenant HTTP mode
Summary
In multi-tenant HTTP mode (ENABLE_MULTI_TENANT=true), an authenticated tenant could, under certain conditions, reach n8n-mcp's local default-scope workflow_versions backups instead of being confined to its own tenant scope. This affects n8n-mcp's own local workflow-version storage, not a normal n8n API capability.
Impact
An authenticated MCP HTTP tenant could read or delete workflow-version backups stored in the default (single-tenant) scope — for example backups left from a prior single-tenant deployment or a migration period. Workflow snapshots may contain sensitive workflow configuration depending on their contents. Single-tenant and stdio deployments are not affected.
Affected versions
<= 2.57.3
Patched version
2.57.4
Remediation
Upgrade to n8n-mcp 2.57.4 or later. The fix requires a complete tenant context in multi-tenant mode and fails closed for workflow-version access that cannot be attributed to a specific tenant.
Workarounds
- Restrict network access to the HTTP endpoint (firewall / reverse proxy / VPN) so only trusted callers can reach it.
- Run in stdio mode, which has no multi-tenant HTTP surface.
- If default-scope backups from a prior single-tenant deployment are not needed, removing them eliminates the exposure.
Credit
Reported by @DavidCarliez.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | n8n-mcp | < 2.57.4 | 2.57.4 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N- Weakness (CWE)
CWE-200, CWE-863- Platform
- npm
- Package
n8n-mcp- Disclosed
- 14.07.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-2cf7-hpwf-47h9 - CC BY 4.0
Vulnerability history: n8n-mcp
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 11
- First → latest
- 04.2026 07.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 6
- Medium 4
Disclosures per year
- 2026: 11
-
n8n-MCP: Incorrect authorization can expose default-scope workflow version backups in multi-tenant HTTP mode this entry
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