Executive brief
n8n is an automation and workflow orchestration platform that allows users to create and edit workflow expressions. An authenticated user can exploit a vulnerability in the VM expression engine to escape its sandbox through prototype pollution, allowing them to execute arbitrary code or crash the application. This impacts both self-hosted and cloud deployments, affecting the availability and security of automation workflows.
Technical details
The vulnerability is a prototype pollution flaw (CWE-1321) in n8n's VM expression engine that allows an authenticated user to abuse array-element access mechanisms to obtain a reference to host built-in objects and pollute their prototypes in the main n8n process. This sandbox escape can lead to arbitrary code execution or denial of service. The attack requires low privileges (authenticated user able to create or edit workflow expressions) and network reachability, with no user interaction needed. The issue has been patched in n8n versions 1.123.67, 2.31.5, and 2.32.1.
Affected products
- n8n n8n < 1.123.67, < 2.31.5, < 2.32.1
Timeline
- 2026-07-22: disclosed
- 2026-07-22: patched: Fixed in versions 1.123.67, 2.31.5, and 2.32.1