CVE-2026-55608Medium· 4.2▾ Sunlitn8n-MCP: Incorrect authorization can expose default-scope workflow version backups in multi-tenant HTTP mode
▾ Sunlit zone — Low / medium · no exploitation signal
impact 23.1 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 16.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via GHSA
0.3%
0.3% → 0.3%
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.
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.
<= 2.57.3
2.57.4
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.
Reported by @DavidCarliez.
n8n-mcp <= 2.57.3Upgrade to a patched release:
n8n-mcp 2.57.4Connected by shared product, vendor, weakness, or advisory.
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