---
id: CVE-2026-93603
title: >-
  vm2 through 3.12.0 (fixed in 3.12.1) does not correctly handle a nullish
  `this` receiver in the apply trap of its bridge (lib/bridge.js): when
  sandboxed code calls a host-provided non-strict (sloppy-mode) function without
  a receiver — e.…
summary: >-
  vm2 through 3.12.0 (fixed in 3.12.1) does not correctly handle a nullish
  `this` receiver in the apply trap of its bridge (lib/bridge.js): when
  sandboxed code calls a host-provided non-strict (sloppy-mode) function without
  a receiver — e.…
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-94
  - CWE-653
vendor: patriksimek
product: vm2
affected:
  - vm2 < 3.12.1
published: '2026-09-18'
updated: '2026-09-22'
sourceUpdated: '2026-09-22T15:17:24.040'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93603'
references:
  - url: 'https://github.com/patriksimek/vm2/security/advisories/GHSA-j89j-5m6r-cr2q'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/vm2-before-3.12.1-sandbox-escape-rce-via-non-strict-host-function
    label: disclosure@vulncheck.com
  - url: 'https://github.com/patriksimek/vm2/security/advisories/GHSA-j89j-5m6r-cr2q'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93603.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-93603'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2537857'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-93603'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93603'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
epss: 0.00726
epssPercentile: 0.52123
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-09-22T14:25:04.925932Z'
ingestedAt: '2026-09-18T13:41:41.662Z'
scores:
  nvd: 10
  vendor: 9.8
---

## Overview

vm2 through 3.12.0 (fixed in 3.12.1) does not correctly handle a nullish `this` receiver in the apply trap of its bridge (lib/bridge.js): when sandboxed code calls a host-provided non-strict (sloppy-mode) function without a receiver — e.g. `fn()`, a detached method, `fn.call()`, `fn.apply(undefined)`, `Reflect.apply(fn, undefined, [])`, or `fn.bind()()` — the undefined receiver is passed straight through to the host call, and V8 substitutes the host realm's global object for `this`. vm2 then wraps and returns that object to the sandbox, giving sandboxed script a live proxy of the host global. This allows a complete sandbox escape: untrusted script can reach `process` and execute arbitrary code/commands on the host (for example via `process.getBuiltinModule('child_process').execSync`). Exploitation requires that the embedding application expose at least one non-strict host function to the sandbox; strict-mode and ES module host functions are not affected.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Critical · affected: Red Hat Developer Hub, Self-service automation portal 2 · no fix planned: Red Hat Developer Hub, Self-service automation portal 2 · updated 2026-09-25 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93603.json)