GHSA-j6r7-6fhx-77wx: n8n-MCP: Cross-tenant access to workflow version backups in multi-tenant HTTP deployments

Summary

In multi-tenant HTTP deployments of n8n-mcp (ENABLE_MULTI_TENANT=true), the locally stored workflow version history was not isolated per tenant. An authenticated tenant could read other tenants' workflow version snapshots, which can include node credential references and authorization headers, and could delete their backups. Affected versions are <= 2.56.0; stdio and single-tenant HTTP deployments are not affected.

Mitigation

Fixed in 2.56.1, which isolates the stored version history per instance; upgrading runs a one-time migration that isolates existing history and clears previously stored, un-scoped backups. Workarounds: set DISABLED_TOOLS=n8n_workflow_versions in the server environment, run each tenant on a separate instance with its own database, or restrict network access to the HTTP endpoint to trusted operators.

Topics

• Model Context Protocol

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