This vulnerability affects vm2 versions 3.10.2 up to but not including 3.11.7 running on Node.js 26. It is caused by a stale PromiseThenLookupChain protector in V8 14.6 that allows Promise.prototype.finally() to bypass vm2's sandbox wrapper protections. An attacker can exploit this by crafting an async function that returns a Promise whose constructor's Symbol.species property is attacker-controlled. This manipulation allows the attacker to access the host Function constructor and the process object, leading to arbitrary code execution outside the sandbox.

Successful exploitation results in a sandbox escape, allowing an attacker to execute arbitrary code on the host system without privileges or user interaction. This compromises the isolation guarantees of vm2, potentially leading to full system compromise.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance.