Security Digest · Vulnerability record
CVE-2026-44008: vm2 has sandbox breakout via `neutralizeArraySpeciesBatch`
vm2 is an open source vm/sandbox for Node.js.
CVSS 9.8 Critical EPSS 0.9% · p59
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.9%, percentile 59: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 59% 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) <= 3.11.1, fixed in 3.11.2. Check your lockfile, including transitive dependencies.
What it is
vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.2, the new method neutralizeArraySpeciesBatch works with objects from the other side but can call into this side via getter on the array prototype exposing objects of the wrong side into the sandbox. This can be used to get host objects and get the host Function object. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system. This vulnerability is fixed in 3.11.2.
From the GitHub advisory
Summary
VM2 suffers from a sandbox breakout vulnerability. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system.
Details
The new method neutralizeArraySpeciesBatch works with objects from the other side but can call into this side via getter on the array prototype exposing objects of the wrong side into the sandbox. This can be used to get host objects and get the host Function object.
PoC
Weakness type: CWE-668, CWE-1100.
Product: vm2 (npm) · Assigned by: GitHub_M · Published: 2026-05-13
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| npm | vm2 | <= 3.11.1 | 3.11.2 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| patriksimek | vm2 | < 3.11.2 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| redhat-SADP | 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- 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): 0.90% probability of exploitation activity in the next 30 days; percentile 59.
Timeline
- — GitHub-reviewed advisory GHSA-9qj6-qjgg-37qq published (critical)
- — CVE record published by GitHub_M
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- access.redhat.com access.redhat.com
Vulnerability records
- GitHub Advisory GHSA-9qj6-qjgg-37qq github.com
- CVE.org record CVE-2026-44008 cve.org
- NVD entry CVE-2026-44008 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- access.redhat.com access.redhat.com
- RHBZ#2477201 bugzilla.redhat.com
- security.access.redhat.com security.access.redhat.com
- github.com github.com