vm2 Sandbox Escape (CVE-2026-43997) Exposes Node.js Hosts
The National Vulnerability Database has issued a critical advisory for CVE-2026-43997, a severe vulnerability in vm2, an open-source sandbox for Node.js. This flaw, present in versions prior to 3.11.0, allows an attacker to escape the sandbox environment and gain access to the host Object. This is a full sandbox bypass, enabling arbitrary code execution on the underlying system.
The mechanism involves leveraging the host Object — specifically, an example cited by the National Vulnerability Database is the use of HostObject.getOwnPropertySymbols to obtain Symbol(nodejs.util.inspect.custom). This technique effectively breaks the isolation vm2 is designed to provide, rendering any security assumptions based on its sandbox invalid. The vulnerability carries a CVSS score of 10.0 (CRITICAL).
This is not a theoretical flaw; it’s a direct path to host compromise. Any application using vm2 for untrusted code execution, such as serverless functions, plugin architectures, or code playgrounds, is at extreme risk. The fix is available in vm2 version 3.11.0, and immediate upgrade is the only viable mitigation.
What This Means For You
- If your Node.js applications use `vm2` to execute untrusted code, you are exposed to full host compromise. Check your dependencies immediately. Upgrade `vm2` to version 3.11.0 or later RIGHT NOW. If you cannot upgrade, isolate these applications completely and consider alternative sandboxing solutions.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
vm2 Sandbox Escape Attempt via Host Object Access - CVE-2026-43997
title: vm2 Sandbox Escape Attempt via Host Object Access - CVE-2026-43997
id: scw-2026-05-13-ai-1
status: experimental
level: critical
description: |
Detects attempts to exploit CVE-2026-43997 by looking for Node.js processes executing commands that reference the specific Symbol used in known exploitation techniques to access the host object and escape the vm2 sandbox.
author: SCW Feed Engine (AI-generated)
date: 2026-05-13
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-43997/
tags:
- attack.execution
- attack.t1059.001
logsource:
category: process_creation
detection:
selection:
Image|contains:
- 'node.exe'
CommandLine|contains:
- 'Symbol(nodejs.util.inspect.custom)'
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-43997 | Sandbox Escape | vm2 Node.js sandbox library |
| CVE-2026-43997 | Sandbox Escape | vm2 versions prior to 3.11.0 |
| CVE-2026-43997 | Sandbox Escape | Obtaining the host Object within vm2 |
| CVE-2026-43997 | Sandbox Escape | Exploiting HostObject.getOwnPropertySymbols to obtain Symbol(nodejs.util.inspect.custom) |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 13, 2026 at 21:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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