CVE-2026-92942 vm2 before 3.11.7 Timeout Bypass via FinalizationRegistry
Attackers can bypass VM timeouts using FinalizationRegistry to execute long-running code, causing host event loop blocking and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-92942?
CVE-2026-92942 is a high-severity denial of service vulnerability in patriksimek vm2, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
vm2 before 3.11.7 (affected versions <= 3.11.6) does not enforce the VM({ timeout }) option on code executed outside the synchronous VM#run() call. The timeout only wraps the single call to _runScript() via doWithTimeout() in lib/vm.js, and FinalizationRegistry and WeakRef are exposed to sandboxed code unmodified (they are not among the hardened globals in lib/setup-sandbox.js). Sandboxed code can register a FinalizationRegistry cleanup callback against an object and then drop the only strong reference to it; vm.run() returns within the configured timeout, but when the V8 garbage collector later reclaims the object it invokes the sandboxed cleanup callback outside any vm2 timeout accounting. A busy loop in that callback blocks the host event loop for an unbounded period, resulting in denial of service. The time of invocation depends on the garbage collector (e.g. under memory pressure or with --expose-gc).
Weakness: CWE-400
Which versions are affected by CVE-2026-92942?
2 open source packages ship an affected version, including vm2.
| Package | Affected | Fixed in |
|---|---|---|
vm2 npm | All versions | 3.11.7 |
vm2 npm | All versions | 3.11.7 |
How do I fix CVE-2026-92942?
Upgrade vm2 to 3.11.7 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-92942 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-92942 exists.
Sources
Also known as CLEANSTART-2026-PF49108, ECHO-84f2-f700-1ce3, GHSA-r4fx-v8hh-22mv, MINI-h86g-9f7f-ghv3, ROOT-APP-NPM-CVE-2026-92942.