Executive brief
n8n is a workflow automation platform that allows users to create and execute workflows using various nodes, including Code nodes that run JavaScript. A vulnerability in the JavaScript task runner allows authenticated users with Code node access to escape the VM sandbox through prototype pollution, enabling them to execute arbitrary commands within the runner container and potentially impact multiple tenants on shared infrastructure. On v1.x instances without task runners enabled, this could compromise the main n8n process itself.
Technical details
This vulnerability is a VM sandbox escape via prototype pollution affecting the JavaScript task runner. The root cause is incomplete prototype freezing: while the runner's initialization freezes globalThis functions, it fails to freeze internal Node.js module constructors like EventEmitter. An authenticated attacker with Code node access can exploit this gap to pollute the EventEmitter prototype, achieving arbitrary code execution within the runner container. Because the polluted prototype persists as a process-wide object, subsequent Code node executions from other tenants on the same shared runner will execute the attacker's injected code. On v1.x without task runners enabled, the vulnerability is more severe as JavaScript executes directly in the main process. The issue is classified as CWE-94 (Code Injection) and has been patched in versions 1.123.69, 2.33.4, and 2.34.1.
Affected products
- n8n n8n before 1.123.69, 2.33.4, and 2.34.1
Timeline
- 2026-08-05: disclosed
- 2026-08-20: advisory