---
title: "CVE-2026-47683: vm2: bufferAllocLimit cap bypassed by Buffer.concat and Buffer.from arrayLike"
url: https://erroneo.us/security/cve/CVE-2026-47683/
description: "CVE-2026-47683 (patriksimek vm2): vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.6, the bufferAllocLimit enforcement in lib/setup-sandbox.js…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-08-17
date_modified: 2026-10-07
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-47683"
kev: false
cvss: 8.7
epss: 0.00538
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-47683: vm2: bufferAllocLimit cap bypassed by Buffer.concat and Buffer.from arrayLike

**Signal:** Normal patch cycle. No exploitation signal; fix it in your next routine update if you are affected. (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 0.5% , percentile 44: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 44% of all scored CVEs (low). 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.
- Editorial verdict: Check exposure. vm2: 22 Critical Sandbox Escapes, Fixed in 3.12.2 — If anything outside your trust boundary can get code into vm2, upgrade to 3.12.2 today and plan to move that code out of process; if vm2 only runs your own code, upgrade on a normal cycle.

## What it is

vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.6, the bufferAllocLimit enforcement in lib/setup-sandbox.js does not cover Buffer.concat(list, totalLength) or Buffer.from(arrayLike) with an attacker-controlled length, allowing sandbox code to perform large synchronous host external-memory allocations that bypass the configured cap and can exhaust the host process. This issue is fixed in version 3.11.6.

## Affected products (CVE record)

- patriksimek vm2: < 3.11.6

## Severity

- GitHub_M CVSS 4.0: 8.7 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`

## 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): 0.54% probability of exploitation activity in the next 30 days; percentile 44.

## Sources

- [CVE.org record CVE-2026-47683](https://www.cve.org/CVERecord?id=CVE-2026-47683)
- [NVD entry CVE-2026-47683](https://nvd.nist.gov/vuln/detail/CVE-2026-47683)
- [github.com](https://github.com/patriksimek/vm2/security/advisories/GHSA-gmc2-2x9w-cgh9)
- [github.com](https://github.com/patriksimek/vm2/commit/3ffb315512e634cf85c447375e85d6c83d00a4bd)
- [github.com](https://github.com/patriksimek/vm2/releases/tag/3.11.6)

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Source page: https://erroneo.us/security/cve/CVE-2026-47683/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt