n8n: Cross-Tenant Module-Cache Poisoning in the JS Task Runner

Summary

## Impact n8n's JavaScript task runner shared one module cache across all users' Code-node executions, so a user able to run a Code node could poison a cached module and alter other users' Code-node executions on the same runner, affecting their confidentiality, integrity, or availability. This is a cross-user isolation break within a single n8n instance. It does not constitute a sandbox escape or remote code execution. All multi-user n8n instances running the JS task runner with built-in or external modules enabled are affected. ## Patches The issue has been fixed in n8n versions 1.123.67, 2.31.5, and 2.32.1. Users should upgrade to one of these versions or later to remediate the vulnerability. ## Workarounds If upgrading is not immediately possible, administrators should consider the following temporary mitigations: - Restrict n8n instance access to fully trusted users only. - Disable built-in and external module access in Code nodes by unsetting `NODE_FUNCTION_ALLOW_BUILTIN` and `NODE_FUNCTION_ALLOW_EXTERNAL`, which removes the poisonable module surface. - Use the external runner mode with a dedicated runner per user or project if your deployment supports it. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.