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CVE-2026-92958 high CVSS 8.5

Privilege Escalation in vm2 (CVE-2026-92958)

Summary

Vulnerability in vm2 (CVE-2026-92958). Data can be tampered with by attackers. Exploitable via DANGEROUS_BUILTINS. Mitigation: upgrade to 3.11.7 or later.

Original description

The description as published by the source.

Summary

NodeVM's builtin wildcard policy can allow sandboxed code to access fs/promises even when the embedder denies fs.

With the following configuration:

require: {
  builtin: ['*', '-fs', '-child_process']
}

require('fs') and require('child_process') are blocked, but require('fs/promises') and require('node:fs/promises') are still available. This allows sandboxed code to create and write files on the host filesystem through the promise-based filesystem API.

Affected Mode

NodeVM.

Affected Configuration

new NodeVM({
  require: {
    builtin: ['*', '-fs', '-child_process']
  }
});

This affects configurations where users rely on negative builtin entries such as -fs to deny filesystem access while using the '*' builtin wildcard.

Affected Files / Functions

  • lib/builtin.js
    • DANGEROUS_BUILTINS
    • BUILTIN_MODULES
    • makeBuiltinsFromLegacyOptions
    • addDefaultBuiltin
  • lib/resolver.js
    • Resolver.resolve
    • Resolver.loadBuiltinModule
  • lib/setup-node-sandbox.js
    • requireImpl

Root Cause

lib/builtin.js builds BUILTIN_MODULES from Node's builtin module list and filters dangerous/default-denied modules. In wildcard mode, negative entries are checked by exact name:

if (builtins.indexOf(`-${name}`) === -1) {
  addDefaultBuiltin(res, name, hostRequire);
}

This means -fs removes only the exact builtin named fs. It does not remove builtin subpaths such as fs/promises.

There i…

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-2026-92958 has been found in vm2.
Attackers can target a specific entry point like DANGEROUS_BUILTINS over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 8.5/10.
What to do: upgrade vm2 to 3.11.7 or later.
If unsure, ask your IT team or search "vm2 CVE-2026-92958" on the vendor's site.

CVE-2026-92958 (vm2) — CWE-269 / CVSS v3 8.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: DANGEROUS_BUILTINS / BUILTIN_MODULES / makeBuiltinsFromLegacyOptions / addDefaultBuiltin
Patched: 3.11.7 — 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-269) exists in vm2. Attackers reach the vulnerable code path via DANGEROUS_BUILTINS.

📍 Affected scope

Check the vendor advisory for the affected versions of vm2. Attack surface: DANGEROUS_BUILTINS / BUILTIN_MODULES / makeBuiltinsFromLegacyOptions / addDefaultBuiltin.

🔥 Severity

Severity: High (CVSS 8.5/10). Data can be tampered with by attackers.

🔧 How to fix

Update to 3.11.7.

🛡️ 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 3.11.7

    ステージング環境で 3.11.7 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":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.11.7"}]}]

References

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