---
title: "CVE-2026-26956: VM2 Has a WASM Sandbox Escape"
url: https://erroneo.us/security/cve/CVE-2026-26956/
description: "CVE-2026-26956 (vm2 (npm)): vm2 is an open source vm/sandbox for Node.js. In version 3.10.4, vm2 is vulnerable to full sandbox escape with arbitrary code…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-05-04
date_modified: 2026-07-15
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-26956"
kev: false
cvss: 9.8
epss: 0.00921
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-26956: VM2 Has a WASM Sandbox Escape

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (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 0.9% , percentile 60: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 60% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes vm2 (npm) <= 3.10.4, fixed in 3.10.5 . Check your lockfile, including transitive dependencies.

## What it is

vm2 is an open source vm/sandbox for Node.js. In version 3.10.4, vm2 is vulnerable to full sandbox escape with arbitrary code execution. Attacker code inside VM.run() obtains host process object and runs host commands with zero host cooperation. This issue has been patched in version 3.10.5.

## Affected packages

- npm `vm2` <= 3.10.4 → fixed: 3.10.5

## Affected products (CVE record)

- patriksimek vm2: = 3.10.4

## Severity

- GitHub_M CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- redhat-SADP CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.92% probability of exploitation activity in the next 30 days; percentile 60.

## Sources

- [GitHub Advisory GHSA-ffh4-j6h5-pg66](https://github.com/advisories/GHSA-ffh4-j6h5-pg66)
- [CVE.org record CVE-2026-26956](https://www.cve.org/CVERecord?id=CVE-2026-26956)
- [NVD entry CVE-2026-26956](https://nvd.nist.gov/vuln/detail/CVE-2026-26956)
- [github.com](https://github.com/patriksimek/vm2/security/advisories/GHSA-ffh4-j6h5-pg66)
- [github.com](https://github.com/patriksimek/vm2/releases/tag/v3.10.5)
- [access.redhat.com](https://access.redhat.com/security/cve/CVE-2026-26956)
- [RHBZ#2466548](https://bugzilla.redhat.com/show_bug.cgi?id=2466548)
- [security.access.redhat.com](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-26956.json)

---
Source page: https://erroneo.us/security/cve/CVE-2026-26956/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt