vm2's Transformer Fast-Path Bypass Exposes Internal State Variable

Exploitation

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

CVSS

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

EPSS

• CVE-2026-44003: 0.25% estimated exploitation activity in the next 30 days; percentile 16.21 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary vm2's code transformer has a performance optimization that skips AST analysis when the code does not contain catch, import, or async keywords. This fast-path bypass allows sandboxed code to directly access the internal VM2INTERNALSTATEDONOTUSEORPROGRAMWILLFAIL variable, which exposes internal security functions (handleException, wrapWith, import). Details In lib/transformer.js:55-57, a regex check /\b(?:catch|import|async)\b/ determines whether AST transformation is needed. If the code does not contain any of these keywords, the transformer returns the code unmodified. When the fast-path is taken: 1. INTERNALSTATENAME identifier check is bypassed: The AST visitor that blocks access to VM2INTERNALSTATEDONOTUSEORPROGRAMWILLFAIL never runs 2. with statement instrumentation is bypassed: with() statements are not wrapped with wrapWith(), enabling scope manipulation 3. The internal state object exposes: handleException(e), wrapWith(x), import(what) While these methods are currently…

Published by the source

7 May 2026, 04:32 UTC

Last modified by the source

14 May 2026, 20:52 UTC

Source last checked

26 Oct 2026, 12:52 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-wp5r-2gw5-m7q7

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-wp5r-2gw5-m7q7

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# Patch Next advisory brief: CVE-2026-44003

Advisory: vm2's Transformer Fast-Path Bypass Exposes Internal State Variable
IDs: CVE-2026-44003, GHSA-wp5r-2gw5-m7q7
Record: https://patchnext.com/advisories/cve-2026-44003 (revision 2, source checked 26 Oct 2026, 12:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: vm2 3.11.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm vm2: affected <= 3.10.5; fixed in 3.11.0

## 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://osv.dev/vulnerability/GHSA-wp5r-2gw5-m7q7 (OSV record GHSA-wp5r-2gw5-m7q7 lists affected ranges: npm vm2 >=0 <3.11.0 (fixed))
- Verified: https://github.com/advisories/GHSA-wp5r-2gw5-m7q7 (GitHub-reviewed advisory GHSA-wp5r-2gw5-m7q7 lists affected ranges: npm vm2 >=0 <=3.10.5)

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