# 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.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 18 Sep 2026
- **Also known as:** CLEANSTART-2026-PF49108, ECHO-84f2-f700-1ce3, GHSA-r4fx-v8hh-22mv, MINI-h86g-9f7f-ghv3, ROOT-APP-NPM-CVE-2026-92942

## 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 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-92942?

2 open source packages ship an affected version, including vm2.


| Package | Ecosystem | 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.

## Is CVE-2026-92942 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-92942 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-92942 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-92942 exists.

Affected packages and fixed versions:
- vm2 (npm): affected all versions; fixed in 3.11.7
- vm2 (npm): affected all versions; fixed in 3.11.7

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-92942/ (Markdown: https://insights.sbomify.com/CVE-2026-92942/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-92942
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-92942
- OSV: https://osv.dev/vulnerability/CVE-2026-92942

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-92942/
Summaries are generated and may contain mistakes; the official description above is the record.