vm2 sandbox escape via JSPI-backed Promise `.finally()` species bypass

CVE-2026-47210

What is CVE-2026-47210?

vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, a sandbox escape vulnerability in vm2 allows arbitrary code execution in the host process when untrusted code is executed with async support on runtimes exposing WebAssembly JSPI (WebAssembly.promising / WebAssembly.Suspending). In the tested configuration, a JSPI-backed Promise can reach Promise.prototype.finally() in a way that bypasses the expected Promise-species hardening and exposes a host-originated rejection object to attacker-controlled species logic, breaking the sandbox boundary. This issue has been patched in version 3.11.4.

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