vm2 has Memory Exhaustion DoS via bufferAllocLimit Bypass

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary: The bufferAllocLimit defense (GHSA-6785-pvv7-mvg7) can be completely bypassed using ArrayBuffer, SharedArrayBuffer, or any TypedArray constructor. These allocate identical host-process RSS through the same V8/libuv C++ allocation path as Buffer.alloc but are not subject to the size cap. Details: The bufferAllocLimit option (vm2 v3.11.0+) caps Buffer.alloc, Buffer.allocUnsafe, Buffer.allocUnsafeSlow, and the deprecated Buffer(N) / new Buffer(N) forms. The cap is enforced in setup-sandbox.js via checkBufferAllocLimit() (line 353-359). However, ArrayBuffer, SharedArrayBuffer, Uint8Array, Float64Array, and all other TypedArray constructors are sandbox-realm V8 intrinsics that allocate host memory through the SAME underlying C++ path (v8::ArrayBuffer::NewBackingStore → ArrayBufferAllocator::Allocate → calloc/malloc). These constructors are NOT intercepted by the bufferAllocLimit defense. A single new ArrayBuffer(N) call with a large N exhausts host RSS in one synchronous…

Published by the source

17 Aug 2026, 17:32 UTC

Last modified by the source

17 Aug 2026, 17:32 UTC

Source last checked

26 Oct 2026, 13:01 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-v836-6xw4-9cx3

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# Patch Next advisory brief: GHSA-v836-6xw4-9cx3

Advisory: vm2 has Memory Exhaustion DoS via bufferAllocLimit Bypass
IDs: GHSA-v836-6xw4-9cx3
Record: https://patchnext.com/advisories/ghsa-v836-6xw4-9cx3 (revision 1, source checked 26 Oct 2026, 13:01 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: vm2 3.11.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm vm2: affected <= 3.11.5; fixed in 3.11.6

## Suggested inspection (read-only)
- `npm ls vm2 --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on vm2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-v836-6xw4-9cx3 (GitHub-reviewed advisory GHSA-v836-6xw4-9cx3 lists affected ranges: npm vm2 >=0 <=3.11.5)

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