Security Digest · Vulnerability record
CVE-2026-47208: vm2 is Vulnerable to Sandbox Breakout Through Promise Species
vm2 is an open source vm/sandbox for Node.js.
CVSS 10.0 Critical EPSS 0.8% · p57
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 0.8%, percentile 57: FIRST’s model estimates a 0.8% chance of exploitation activity in the next 30 days, higher than 57% 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) <= 3.11.3, fixed in 3.11.4. Check your lockfile, including transitive dependencies.
What it is
vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, 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. This issue has been patched in version 3.11.4.
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 localPromise constructor was changed to call this.then(undefined, eater) to ensure a rejected promise is always used. However, this is missing a call to resetPromiseSpecies to ensure that this has no special species. Since the species can be changed a custom promise can be used to supply a custom reject method to the executor allowing to get a raw host error and escape the sandbox.
PoC
Weakness type: CWE-913.
Product: vm2 (npm) · Assigned by: GitHub_M · Published: 2026-06-12
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| npm | vm2 | <= 3.11.3 | 3.11.4 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| patriksimek | vm2 | < 3.11.4 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 10 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H |
| GitHub | 3.1 | 10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: changed (can affect other components)
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): 0.83% probability of exploitation activity in the next 30 days; percentile 57.
Timeline
- — GitHub-reviewed advisory GHSA-76w7-j9cq-rx2j 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.
Vulnerability records
- GitHub Advisory GHSA-76w7-j9cq-rx2j github.com
- CVE.org record CVE-2026-47208 cve.org
- NVD entry CVE-2026-47208 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com