CVE-2026-92955: vm2 sandbox escape in NodeVM via __proto__ manipulation

CVE-2026-92955 · Severity: critical · CVSS 10 · Published 2026-09-17

vm2 is a popular JavaScript sandbox used to safely execute untrusted code in Node.js applications. This vulnerability allows attackers to break out of the sandbox by accessing the host's prototype chain through console objects and overwriting core event handling mechanisms, effectively gaining full code execution with the privileges of the host process. Organizations using vm2 to isolate user-supplied scripts are at immediate risk of complete system compromise.

Technologies: vm2 (npm). Vendors: npm.

Quick answers

Is CVE-2026-92955 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-92955 being exploited in the wild.
How severe is CVE-2026-92955?
Critical severity, with a CVSS score of 10, published 17 September 2026.
Which products and versions are affected?
vm2 (npm) <= 3.11.7, SEMVER:introduced=0,fixed=3.11.8.
Is there a fix for CVE-2026-92955?
Yes. vm2 (npm): upgrade to 3.11.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-92955 attacked?
It is attacked over the network.
Am I affected by CVE-2026-92955?
Check whether you run vm2 (npm) 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

  • vm2 (npm): upgrade to 3.11.8 or later
    npm install vm2@3.11.8

Technical details

This sandbox escape exploits the ability to access the host __proto__ getter/setter through console._stdout and console._stderr objects. The attack chain involves traversing the prototype chain (WriteStream → Socket → Duplex → Readable → Stream → EventEmitter) to gain access to EventEmitter.prototype, then overwriting the emit method. By triggering process events (such as exit or unhandledRejection), attackers execute arbitrary code in the process context. The vulnerability bypasses --disallow-code-generation-from-strings, which normally blocks code generation escapes. A fix is available in version 3.11.8.

Affected products

  • vm2 vm2 before 3.11.8

Identifiers

  • CVE-2026-92955
  • GHSA-88hf-g992-jg85

Timeline

  • 2026-08-27: disclosed: GitHub Security Advisory published
  • 2026-09-17: advisory: CVE-2026-92955 published
  • 2026-09-17: patched: Patch available in version 3.11.8

References

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