CVE-2026-92934: vm2 sandbox escape in AggregateError handling

CVE-2026-92934 · Severity: critical · CVSS 9 · Published 2026-09-17

vm2 is a JavaScript sandbox designed to safely isolate untrusted code execution from the host system. A flaw in how it sanitizes exception objects allows attackers to break out of the sandbox and execute arbitrary commands on the host machine with full privileges. The vulnerability occurs when catching specific types of exceptions, enabling an attacker to access the host's file system, environment variables, and run arbitrary processes.

Technologies: vm2 (npm). Vendors: npm.

Quick answers

Is CVE-2026-92934 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-92934 being exploited in the wild.
How severe is CVE-2026-92934?
Critical severity, with a CVSS score of 9, 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-2026-92934?
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-2026-92934 attacked?
It is attacked over the network.
Am I affected by CVE-2026-92934?
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

The vulnerability is an incomplete fix bypass affecting Error.cause sanitization in the handleException function (lib/setup-sandbox.js). When an AggregateError object containing host references is revisited within a single exception handler traversal (through self-cycles, mutual-cycles, or duplicate references in the errors array), the cycle detection short-circuit at line 1819 returns the raw unsanitized host proxy instead of the memoized sandbox-realm replacement. This occurs because sanitizeAggregateError rebuilds host-wrapped carriers into fresh LocalAggregateError objects without sealing the original, allowing the live proxy to be re-embedded in the sanitized errors array. Attack requires embedder to expose a host function that throws such a crafted AggregateError; sandbox code catches it and accesses the leak via e.errors[index].property chains, achieving full RCE via child_process.execSync and process information disclosure. Fixed in vm2 3.11.8.

Affected products

  • vm2 vm2 before 3.11.8

Identifiers

  • CVE-2026-92934
  • GHSA-x965-fc75-jpqh

Timeline

  • 2026-08-27: disclosed: GHSA-x965-fc75-jpqh published
  • 2026-09-17: advisory: CVE-2026-92934 published on NVD
  • 2026: patched: Fix released in vm2 3.11.8

References

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