CVE-2026-47208: patriksimek vm2 sandbox breakout via Promise species hijack

CVE-2026-47208 · Severity: critical · CVSS 10 · Published 2026-06-12

vm2 is a popular Node.js library used to run untrusted code in a restricted 'sandbox' environment to prevent it from accessing the host system. A critical flaw allows an attacker to bypass these restrictions and escape the sandbox. If exploited, an attacker can execute unauthorized commands on the underlying server, potentially leading to full system takeover and data theft.

Technologies: vm2 (npm). Vendors: npm.

Quick answers

Is CVE-2026-47208 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-47208 being exploited in the wild.
How severe is CVE-2026-47208?
Critical severity, with a CVSS score of 10, published 12 June 2026.
Which products and versions are affected?
vm2 (npm) <= 3.11.3, SEMVER:introduced=0,fixed=3.11.4.
Is there a fix for CVE-2026-47208?
Yes. vm2 (npm): upgrade to 3.11.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-47208 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-47208?
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 3.11.4 or later
    npm install vm2@3.11.4

Technical details

A sandbox breakout exists in vm2 due to improper control of dynamically-managed code resources (CWE-913) within the Promise constructor. Specifically, the 'localPromise' constructor fails to call 'resetPromiseSpecies' before invoking the 'then' method. An attacker can exploit this by hijacking the 'Symbol.species' protocol to provide a custom constructor, allowing them to capture V8's internal resolution capabilities. By combining this with a recursion-induced RangeError, the attacker can obtain a reference to a host-realm Error object and use its constructor to access the host's 'process' object and execute arbitrary commands via 'child_process'. This issue is patched in version 3.11.4.

Affected products

  • patriksimek vm2 <= 3.11.3

Identifiers

  • CVE-2026-47208
  • GHSA-76w7-j9cq-rx2j

Timeline

  • 2026-05-17: patched: Fix committed to repository
  • 2026-05-18: advisory: GitHub Security Advisory published
  • 2026-06-12: disclosed: CVE published to NVD

References

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