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

> Attackers can escape the vm2 sandbox and execute arbitrary code by loading excluded builtins via the module builtin, requiring the module builtin to be allowed in configuration.

- **Severity:** Critical 9.9 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 May 2026
- **Updated:** 7 Sep 2026
- **Also known as:** GHSA-947f-4v7f-x2v8, ROOT-APP-NPM-CVE-2026-43999

## What is CVE-2026-43999?

CVE-2026-43999 is a critical code injection vulnerability in patriksimek vm2, published on 13 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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 child_process and achieve remote code execution. This vulnerability is fixed in 3.11.0.

Weakness: CWE-829 (Inclusion of Functionality from Untrusted Control Sphere), CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-43999?

2 open source packages ship an affected version, including vm2. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `vm2` | npm | From 3.10.5 | 3.11.0 |
| `vm2` | npm | From 3.10.5 | 3.11.0 |

Products: Vm2 Project Vm2.

## How do I fix CVE-2026-43999?

Upgrade vm2 to 3.11.0 or later.

## Is CVE-2026-43999 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43999 exists.

## Other vulnerabilities in patriksimek vm2

- [CVE-2026-43997](https://insights.sbomify.com/CVE-2026-43997/): vm2: Sandbox Escape (critical 10.0)
- [CVE-2026-44005](https://insights.sbomify.com/CVE-2026-44005/): vm2: Sandbox escape (critical 10.0)
- [CVE-2026-44006](https://insights.sbomify.com/CVE-2026-44006/): vm2: Sandbox Escape (critical 10.0)
- [CVE-2023-29017](https://insights.sbomify.com/CVE-2023-29017/): vm2 Sandbox Escape vulnerability (critical 10.0)
- [CVE-2022-36067](https://insights.sbomify.com/CVE-2022-36067/): vm2 vulnerable to Sandbox Escape before v3.9.11 (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43999 and fix it if it is affected.

What it is: CVE-2026-43999 is a critical code injection vulnerability in patriksimek vm2, published on 13 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43999 exists.

Affected packages and fixed versions:
- vm2 (npm): affected from 3.10.5; fixed in 3.11.0
- vm2 (npm): affected from 3.10.5; fixed in 3.11.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-43999/ (Markdown: https://insights.sbomify.com/CVE-2026-43999/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43999
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43999
- OSV: https://osv.dev/vulnerability/CVE-2026-43999

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43999/
Summaries are generated and may contain mistakes; the official description above is the record.