---
title: "CVE-2026-43999: vm2 has a NodeVM builtin allowlist bypass via `module` builtin's `Module._load` that allows sandbox escape"
url: https://erroneo.us/security/cve/CVE-2026-43999/
description: "CVE-2026-43999 (vm2 (npm)): vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.0, NodeVM's builtin allowlist can be bypassed when the module…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-05-13
date_modified: 2026-09-07
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-43999"
kev: false
cvss: 9.9
epss: 0.0097
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-43999: vm2 has a NodeVM builtin allowlist bypass via `module` builtin's `Module._load` that allows sandbox escape

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 1.0% , percentile 61: FIRST’s model estimates a 1.0% chance of exploitation activity in the next 30 days, higher than 61% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes vm2 (npm) = 3.10.5, fixed in 3.11.0 . Check your lockfile, including transitive dependencies.

## What it is

vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.0, NodeVM's builtin allowlist can be bypassed when the module builtin is allowed (including via the '' wildcard). The module builtin exposes Node's Module.load(), which loads any module by name directly in the host context, completely bypassing vm2's builtin restriction. This allows sandboxed code to load excluded builtins like childprocess and achieve remote code execution. This vulnerability is fixed in 3.11.0.

## Affected packages

- npm `vm2` = 3.10.5 → fixed: 3.11.0

## Affected products (CVE record)

- patriksimek vm2: < 3.11.0

## Severity

- GitHub_M CVSS 3.1: 9.9 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`
- redhat-SADP CVSS 3.1: 9.9 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.9 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.97% probability of exploitation activity in the next 30 days; percentile 61.

## Sources

- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:50850)
- [GitHub Advisory GHSA-947f-4v7f-x2v8](https://github.com/advisories/GHSA-947f-4v7f-x2v8)
- [CVE.org record CVE-2026-43999](https://www.cve.org/CVERecord?id=CVE-2026-43999)
- [NVD entry CVE-2026-43999](https://nvd.nist.gov/vuln/detail/CVE-2026-43999)
- [github.com](https://github.com/patriksimek/vm2/security/advisories/GHSA-947f-4v7f-x2v8)
- [access.redhat.com](https://access.redhat.com/security/cve/CVE-2026-43999)
- [RHBZ#2477196](https://bugzilla.redhat.com/show_bug.cgi?id=2477196)
- [security.access.redhat.com](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43999.json)

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Source page: https://erroneo.us/security/cve/CVE-2026-43999/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt