CVE-2026-55608: CWE-200: Exposure of Sensitive Information to an Unauthorized Actor in czlonkowski n8n-mcp
Description
## 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.
CVSS v3.1
Score 4.2medium
Affected software
czlonkowski
n8n-mcp
pkg:github/czlonkowski/n8n-mcpRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in n8n-mcp (CVE-2026-55608) involves improper access control in multi-tenant HTTP mode with ENABLE_MULTI_TENANT=true. Authenticated tenants could access default-scope workflow_versions backups rather than being restricted to their own tenant scope. This exposure allows unauthorized access or deletion of workflow-version backups from previous single-tenant deployments or migrations. The issue is fixed in version 2.57.4.
Potential Impact
An authenticated tenant with low privileges could gain unauthorized read or delete access to workflow version backups belonging to other tenants or prior single-tenant deployments. This leads to exposure of sensitive workflow backup data and potential data loss. The impact is limited to confidentiality and integrity with no availability impact.
Mitigation Recommendations
Upgrade n8n-mcp to version 2.57.4 or later, where this access control issue is fixed. There is no indication of alternative mitigations or temporary workarounds. Patch status is confirmed fixed in 2.57.4.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-16T23:31:22.445Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a57f59668715ace437838dc
Added to database: 07/15/2026, 21:03:18 UTC
Last enriched: 07/22/2026, 22:54:23 UTC
Last updated: 10/14/2026, 18:48:21 UTC
Views: 164
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