CVE-2026-100722: vm2 before 3.12.2 Host Process Termination via Construct Trap

Severity: medium (CVSS 6.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-27 · updated 2026-09-28
Weakness: CWE-248

Description

vm2 before 3.12.2 does not apply host-side Promise rejection handling in the sandbox-to-host construct trap. In BaseHandler, the apply trap calls markHostPromiseHandled() on the returned value, but the adjacent construct path returns the result of Reflect.construct without the same sanitization. If an embedder exposes a constructable host function whose constructor returns a native rejected Promise, an untrusted script executed via VM.run can invoke it with `new` and ignore the result; the rejected host Promise crosses the bridge unhandled and, under Node's strict unhandled-rejection policy, is promoted to an uncaught exception that terminates the host process.

Affected products

patriksimek vm2: before 3.12.2 — fixed in 3.12.2

How to fix

Upgrade to a fixed version: patriksimek vm2 3.12.2. Check the vendor advisory for mitigations.

References

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