---
id: GHSA-43rv-jrfh-9mrr
title: >-
  Duplicate Advisory: vm2: NodeVM zlib Buffers expose pooled host memory across
  the VM boundary
summary: >-
  Duplicate Advisory: vm2: NodeVM zlib Buffers expose pooled host memory across
  the VM boundary
severity: medium
cvss: 7.5
cwe:
  - CWE-200
vendor: vm2
product: vm2
ecosystem: npm
affected:
  - vm2 < 3.12.2
patched:
  - vm2 3.12.2
published: '2026-09-27'
updated: '2026-10-05'
sourceUpdated: '2026-10-05T22:59:46Z'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-43rv-jrfh-9mrr'
references:
  - url: 'https://github.com/patriksimek/vm2/security/advisories/GHSA-489w-w794-jq94'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100723'
  - url: >-
      https://github.com/patriksimek/vm2/commit/4f2508abeb252aa86eb6761c78b3b000248fb089
  - url: >-
      https://github.com/patriksimek/vm2/commit/5214b02ef13b82497fcb917b45320dfd014ffd09
  - url: >-
      https://www.vulncheck.com/advisories/vm2-before-3.12.2-memory-disclosure-via-zlib-buffer-pool
  - url: 'https://github.com/advisories/GHSA-43rv-jrfh-9mrr'
tags:
  - ghsa
  - npm
ingestedAt: '2026-10-05T23:36:21.170Z'
---

## Overview

## Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-489w-w794-jq94. This link is maintained to preserve external references.

## Original Description
vm2 before 3.12.2 does not apply its Buffer backing-store ownership invariant (byteOffset === 0 and buffer.byteLength === length) to Buffers returned from host builtin modules. When an application explicitly exposes Node's zlib module through NodeVM's builtin allowlist (require: { builtin: ['zlib'] }), zlib.deflateSync can return a Buffer backed by Node's shared small-buffer pool whose .buffer is the entire pool. Untrusted guest code can construct a full-width view of that ArrayBuffer (Buffer.from(result.buffer, 0, result.buffer.byteLength)) to read and modify bytes belonging to unrelated host buffers, disclosing and corrupting host-realm memory across the sandbox boundary.

## Affected packages

- `vm2 < 3.12.2`

## Remediation

Upgrade to a patched release:

- `vm2 3.12.2`