---
id: CVE-2026-93606
title: >-
  vm2 (npm) versions 3.12.0 and earlier contain a sandbox escape in `VM` and
  `NodeVM`
summary: >-
  vm2 (npm) versions 3.12.0 and earlier contain a sandbox escape in `VM` and
  `NodeVM`. When an embedder exposes a host API that returns a host-realm
  Promise, the bridge's rejection sanitizer (hostPromiseSanitizeReject /
  makeSanitizedPromis…
severity: critical
cvss: 10
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H'
cwe:
  - CWE-693
vendor: patriksimek
product: vm2
affected:
  - vm2 < 3.12.1
published: '2026-09-18'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T18:18:31.267'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93606'
references:
  - url: 'https://github.com/patriksimek/vm2/security/advisories/GHSA-6454-5x88-m6jw'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/vm2-before-3.12.1-sandbox-escape-via-promise-symbol-species
    label: disclosure@vulncheck.com
  - url: 'https://github.com/patriksimek/vm2/security/advisories/GHSA-6454-5x88-m6jw'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-09-18T17:48:22.994448Z'
ingestedAt: '2026-09-18T13:41:41.661Z'
epss: 0.00518
epssPercentile: 0.42896
---

## Overview

vm2 (npm) versions 3.12.0 and earlier contain a sandbox escape in `VM` and `NodeVM`. When an embedder exposes a host API that returns a host-realm Promise, the bridge's rejection sanitizer (hostPromiseSanitizeReject / makeSanitizedPromiseCallback / normalizeHostPromiseCallbacks in lib/bridge.js) only wraps `then`/`catch` rejection slots that hold a function, and the sandbox-side `Symbol.species`/`.then` neutralization is installed only on the sandbox intrinsic `Promise.prototype`, so it never applies to a host Promise. Code running inside the sandbox can overwrite `p.constructor[Symbol.species]` on the host Promise and then call `p.then()` with no `onRejected` handler; V8 substitutes its internal Thrower, which re-throws the raw host rejection value into a resolve/reject closure captured by the attacker. This delivers an unsanitized, fully functional bridge proxy of the host object to sandboxed code, bypassing handleException and hostPromiseSanitizeReject. If the rejection value is host-pivotable (for example a host `process` object), this results in arbitrary code execution on the host. Fixed in 3.12.1.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.