Security Digest · Vulnerability record
CVE-2026-44009: vm2 has Sandbox Breakout Through Null Proto Exception
vm2 is an open source vm/sandbox for Node.js.
CVSS 9.8 Critical EPSS 0.7% · p53
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 0.7%, percentile 53: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 53% 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) < 3.11.2, 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, 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
In handleException due to // SECURITY (post-GHSA-mpf8 hardening): use from (not ensureThis) exceptions with a null proto will be assumed to come from the other side and being proxied. Therefore, it is possible to get the proxied and unproxied object of a sandbox object with a null proto when thrown and then catched which allows to get the host Function object.
PoC
Weakness type: CWE-668, CWE-653.
Product: vm2 (npm) · Assigned by: GitHub_M · Published: 2026-05-13
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| npm | vm2 | < 3.11.2 | 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): 0.71% probability of exploitation activity in the next 30 days; percentile 53.
Timeline
- — GitHub-reviewed advisory GHSA-9vg3-4rfj-wgcm 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-9vg3-4rfj-wgcm github.com
- CVE.org record CVE-2026-44009 cve.org
- NVD entry CVE-2026-44009 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- access.redhat.com access.redhat.com
- RHBZ#2477185 bugzilla.redhat.com
- security.access.redhat.com security.access.redhat.com
- github.com github.com