# CVE-2026-44000: vm2: sandbox boundary bypass via host Promise resolution preserving host object identity

> Attackers can bypass sandbox boundaries in vm2 by exploiting host Promise resolution, leading to code execution and privilege escalation.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 May 2026
- **Updated:** 13 May 2026
- **Also known as:** GHSA-mpf8-4hx2-7cjg, ROOT-APP-NPM-CVE-2026-44000

## What is CVE-2026-44000?

CVE-2026-44000 is a medium-severity code injection vulnerability in patriksimek vm2, published on 13 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.0, a sandbox boundary violation in vm2 allows host object identity to cross into the sandbox through host Promise resolution. When a host-side Promise that resolves to a host object is exposed to the sandbox, the value delivered to the sandbox .then() callback preserves host identity. This allows the sandbox to interact with the host object directly, including performing identity checks using host-side WeakMap and mutating host object state from inside the sandbox. This behavior occurs because the Promise fulfillment wrapper uses ensureThis() instead of the stronger cross-realm conversion path (from() / proxy wrapping). If no prototype mapping is found, ensureThis() returns the original object. As a result, objects resolved by host Promises can cross the sandbox boundary without proper isolation. This vulnerability is fixed in 3.11.0.

Weakness: CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-44000?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `vm2` | npm | All versions | 3.11.0 |
| `vm2` | npm | All versions | 3.11.0 |

Products: Vm2 Project Vm2.

## How do I fix CVE-2026-44000?

Upgrade vm2 to 3.11.0 or later.

## Is CVE-2026-44000 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44000 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-2026-44000 and fix it if it is affected.

What it is: CVE-2026-44000 is a medium-severity code injection vulnerability in patriksimek vm2, published on 13 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44000 exists.

Affected packages and fixed versions:
- vm2 (npm): affected all versions; fixed in 3.11.0
- vm2 (npm): affected all versions; 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-2026-44000/ (Markdown: https://insights.sbomify.com/CVE-2026-44000/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44000
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44000
- OSV: https://osv.dev/vulnerability/CVE-2026-44000

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44000/
Summaries are generated and may contain mistakes; the official description above is the record.