Node.js vm: How to cancel Script.runInNewContext()?

I want to use the vm module as a safe way to run external code. It works pretty well, but there is one issue left:

var UNKNOWN_CODE = "while(true){}";

var vm = require("vm");

var obj = {};
var ctx = vm.createContext(obj);

var script = vm.createScript(UNKNOWN_CODE);

script.runInNewContext(ctx);

console.log("finished"); //never executed

Is there any way to cancel the execution (e.g. if it lasts for more than 5s)?

Thanks in advance!