MEDIUM

GHSA-hx4h-vr3m-45vh

n8n: Prototype Pollution via VM Expression Engine Sandbox Escape Leads to Denial of Service

Quick fix

GHSA-hx4h-vr3m-45vh — n8n: upgrade to the fixed version with the command below.

npm install n8n@1.123.67

Details

## Impact

An authenticated user able to create or edit a workflow expression could abuse the expression engine's array-element access to obtain a reference to a host built-in and pollute its prototype in the main n8n process, leading to a denial of service.

Both self-hosted and cloud instances running the VM expression engine 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 the VM expression engine if an alternative is available for your deployment.

These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.