# vm2 sandbox escape via WebAssembly.compileStreaming Promise species bypass

Source: https://junglewise.ai/threats/duplicate-advisory-vm2-sandbox-escape-via-webassembly-compilestreaming-d9f7d88d  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-17. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

Severity: critical · CVSS 10 · Published 2026-09-17

vm2 is a JavaScript sandbox library used to safely execute untrusted code in isolation. A critical vulnerability allows attackers running code in a default vm2 sandbox on Node.js 26 to escape the sandbox and gain access to the host system's filesystem and other capabilities. The exploit requires no special configuration and works immediately when code executes within the sandbox.

Technologies: [vm2 (npm)](https://junglewise.ai/threats/technologies/vm2), [Patrik Simek Vm2](https://junglewise.ai/threats/technologies/patrik-simek-vm2). Vendors: [npm](https://junglewise.ai/threats/vendors/npm), [Patrik Simek](https://junglewise.ai/threats/vendors/patrik-simek).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** Critical severity, with a CVSS score of 10, published 17 September 2026.

**Which products and versions are affected?** vm2 (npm) >= 3.10.1, <= 3.11.6; Patrik Simek Vm2 3.10.1 through 3.11.6.

**Is there a fix for This vulnerability?** Yes: fixed in 3.11.7. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is This vulnerability attacked?** It is attacked over the network, in a software library.

**Am I affected?** Check whether you run vm2 (npm) or Patrik Simek Vm2 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 3.11.7

## Technical details

vm2 versions 3.10.1 through 3.11.6 contain a sandbox escape triggered via WebAssembly.compileStreaming and WebAssembly.instantiateStreaming, which can produce a raw host-realm Promise. An attacker can manipulate Symbol.species on Promise.prototype.finally to intercept the rejection handler, receive a host error object, and walk the constructor chain to recover the host process object, gaining full Node.js capabilities including module access. This is a bypass of the JSPI-related fix in earlier patches.

## Affected products

- Patrik Simek vm2 3.10.1 through 3.11.6

## Timeline

- 2026-09-17: disclosed
- 2026-10-05: advisory: advisory withdrawn as duplicate of GHSA-wjwh-qqvp-g4p4

## References

- [https://api.github.com/users/portyu9](https://api.github.com/users/portyu9)

## Related threats

- [vm2 NodeVM path bypass in custom resolution](https://junglewise.ai/threats/duplicate-advisory-vm2-nodevm-custom-resolution-bypasses-external-path-5d3a7272)
- [vm2 NodeVM zlib buffer pool information disclosure](https://junglewise.ai/threats/duplicate-advisory-vm2-nodevm-zlib-buffers-expose-pooled-host-memory-6007c734)
- [vm2 host Promise rejection denial of service in construct trap](https://junglewise.ai/threats/duplicate-advisory-vm2-host-promise-rejection-from-an-exposed-f7aba6ba)
- [vm2 sandbox escape via Buffer backing-store ownership bypass](https://junglewise.ai/threats/cve-2026-100723-vm2-before-3-12-2-does-not-apply-its-buffer-backing-store)
- [vm2 unhandled Promise rejection in construct trap](https://junglewise.ai/threats/cve-2026-100722-vm2-before-3-12-2-does-not-apply-host-side-promise-rejection)