AIKIDO-2026-552585

TL;DR

n8n-mcp stores automatic workflow version backups in a local workflow_versions table that lacked any per-tenant scoping. In multi-tenant HTTP deployments the n8n_workflow_versions tool queries rows by a predictable sequential integer ID without verifying that the calling tenant owns the record. An authenticated tenant can enumerate IDs to read, roll back, delete, or truncate other tenants' snapshots, which include full node definitions containing credential references and authorization headers. The fix adds an instance_id column, scopes every read, list, get, delete, rollback, and prune query to the calling instance, and clears legacy un-scoped backups during migration.