Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2026-92959 high CVSS 7.1

Vulnerability in vm2 (CVE-2026-92959)

Summary

Vulnerability in vm2 (CVE-2026-92959). Risk of unauthorized operations or information disclosure. Exploitable via allowAsync. Mitigation: upgrade to 3.11.8 or later.

Original description

The description as published by the source.

Summary

When allowAsync is set to false, vm2 is expected to reject attempts to run asynchronous code. Direct use of Promise.prototype.then is blocked, but Promise static methods still assimilate attacker-controlled thenables. Promise.resolve(thenable), Promise.all([thenable]), Promise.race([thenable]), Promise.any([thenable]), and Promise.allSettled([thenable]) can invoke the thenable's then method in a microtask after VM.run() or NodeVM.run() has already returned.

This bypasses the documented async-execution restriction and runs outside the configured timeout, allowing sandboxed code to continue executing after the host believes execution is complete.

Details

The documented VM option says allowAsync: false should cause attempts to run async code to throw a VMError; README.md:139-145 also recommends using it with timeout. The implementation enforces part of this policy by replacing localPromise.prototype.then with an AsyncErrorHandler when async is disabled:

  • lib/setup-sandbox.js:1629-1637 defines AsyncErrorHandler, whose apply and construct traps throw VMError: Async not available.
  • lib/setup-sandbox.js:1743-1752 installs that handler on localPromise.prototype.then when allowAsync is false.

However, Promise static methods are still exposed and rebound to localPromise:

  • lib/setup-sandbox.js:1816-1819 wraps Promise.all.
  • lib/setup-sandbox.js:1821-1824 wraps Promise.race.
  • `lib/setup-sandbox.js:1826…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-92959 has been found in vm2.
Attackers can target a specific entry point like allowAsync over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.1/10.
What to do: upgrade vm2 to 3.11.8 or later.
If unsure, ask your IT team or search "vm2 CVE-2026-92959" on the vendor's site.

CVE-2026-92959 (vm2) — CWE-693 / CVSS v3 7.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: allowAsync / false / Promise.prototype.then / then
Patched: 3.11.8 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-693) exists in vm2. Attackers reach the vulnerable code path via allowAsync.

📍 Affected scope

Check the vendor advisory for the affected versions of vm2. Attack surface: allowAsync / false / Promise.prototype.then / then.

🔥 Severity

Severity: High (CVSS 7.1/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 3.11.8.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'vm2' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'vm2' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で vm2 を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade vm2 to 3.11.8

    ステージング環境で 3.11.8 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

npm vm2
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.11.8"}]}]

References

We use cookies for analytics and ad measurement. This setting applies to all Game co., Ltd. sites. Details