CVE-2026-92959vm2 before 3.11.8 allowAsync Bypass via Promise Thenable
Updated under an hour ago ()
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It affects patriksimek vm2. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.1 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H
- Weakness (CWE)
- CWE-693
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Deferred
- Record last updated
- Sep 21, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
patriksimek vm2 patriksimek:vm2 (from the name) | before 3.11.8; 3.11.8 not affected | CNA record |
References
- https://github.com/patriksimek/vm2/security/advisories/GHSA-f8gf-w286-fmq2vendor-advisory
- https://www.vulncheck.com/advisories/vm2-before-3.11.8-allowasync-bypass-via-promise-thenablethird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.