CVE-2026-93606

Critical CVSS 10

Published 2026-09-18 · last changed 2026-09-18

The fix

We hold no Microsoft remediation data for CVE-2026-93606, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

vm2 (npm) versions 3.12.0 and earlier contain a sandbox escape in `VM` and `NodeVM`. When an embedder exposes a host API that returns a host-realm Promise, the bridge's rejection sanitizer (hostPromiseSanitizeReject / makeSanitizedPromiseCallback / normalizeHostPromiseCallbacks in lib/bridge.js) only wraps `then`/`catch` rejection slots that hold a function, and the sandbox-side `Symbol.species`/`.then` neutralization is installed only on the sandbox intrinsic `Promise.prototype`, so it never applies to a host Promise. Code running inside the sandbox can overwrite `p.constructor[Symbol.species]` on the host Promise and then call `p.then()` with no `onRejected` handler; V8 substitutes its internal Thrower, which re-throws the raw host rejection value into a resolve/reject closure captured by the attacker. This delivers an unsanitized, fully functional bridge proxy of the host object to sandboxed code, bypassing handleException and hostPromiseSanitizeReject. If the rejection value is host-pivotable (for example a host `process` object), this results in arbitrary code execution on the host. Fixed in 3.12.1.

Sources

NVD record for CVE-2026-93606

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H