Incorrect Authorization Affecting vm2 package, versions <3.12.2
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-JS-VM2-20158386
- published27 Sept 2026
- disclosed27 Sept 2026
- creditUnknown
Introduced: 27 Sep 2026
NewCVE-2026-100721 (opens in a new tab)How to fix?
Upgrade vm2 to version 3.12.2 or higher.
Overview
vm2 is a sandbox that can run untrusted code with whitelisted Node's built-in modules.
Affected versions of this package are vulnerable to Incorrect Authorization via LegacyResolver.isPathAllowed in lib/resolver-compat.js, which uses a raw path.startsWith(mod.path) check to authorize module loads against an allowlisted external module path. Because startsWith performs string prefix matching without enforcing a path boundary, a sibling package whose name shares a prefix with an allowlisted package (e.g., foo2 when foo is allowlisted) passes the check: the stripped remainder (2/index.js) contains no node_modules segment, so the subsequent guard does not catch it. An attacker who controls code running inside the sandbox under an external: {modules: ['foo'], transitive: false} configuration can therefore require an un-allowlisted sibling package, escaping the intended module boundary and gaining access to arbitrary modules the embedder never authorized.