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CVE-2026-92959GHSA-F8GF-W286-FMQ2

vm2 before 3.11.8 allowAsync Bypass via Promise Thenable

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 3.11.8
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: poc
  • Automatable: no
  • Technical impact: partial

Summary

vm2 before 3.11.8 does not fully enforce the allowAsync: false option in VM and NodeVM. While localPromise.prototype.then is replaced with a handler that throws 'Async not available', the sandbox's Promise static methods (Promise.resolve, Promise.all, Promise.race, Promise.any, and Promise.allSettled) still assimilate attacker-supplied thenables: native promise resolution performs PromiseResolveThenableJob and invokes the sandboxed code's then method in a microtask without passing through the patched then, so the async restriction is never applied. As a result, sandboxed script can schedule work that runs after VM.run() or NodeVM.run() has returned and outside the configured timeout, continuing to execute after the host believes execution is complete.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • patriksimek vm2

    fixed in 3.11.8

  • vm2npm

    fixed in 3.11.8

References 2

GitHub · patriksimek/vm2

vulncheck.com