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CVE-2026-92955 critical CVSS 10.0

Vulnerability in vm2 (CVE-2026-92955)

Summary

Vulnerability in vm2 (CVE-2026-92955). Successful exploitation can lead to full system takeover. Exploitable via __proto__. Mitigation: upgrade to 3.11.8 or later.

Original description

The description as published by the source.

Summary

It being possible to obtain the host __proto__ getter/setter, has been used in many reports:

Yet it was never patched...

This can, still, be used to escape the sandbox, one example (I'm sure there's other ways as well), is via console._stdout/console._stderr (NodeVM with console: 'inherit', which is the default)

Details

The prototype chain for console._stdout/console._stderr is:

_stdout / _stderr
-> WriteStream (TTY only)
-> Socket
-> Duplex
-> Readable
-> Stream
-> EventEmitter

process is an EventEmitter, and nothing stops us from writing things to EventEmmiter.prototype

By overwriting EventEmmiter.prototype.emit with a function, and making process emit an event (e.g. exit, unhandledRejection etc.), we can execute code with this being process.

This also bypasses --disallow-code-generation-from-strings, which blocks the "usual" escape of obtaining the host function constructor.

PoC

const { NodeVM } = require("vm2");

code = `
const gP = Buffer.call.call(__lookupGetter__,67,'__proto__');

// vm __proto__ getter
console.log(__lookupGetter__.call(0,'__proto__').call(console._stderr)); // [Object:…

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-2026-92955 has been found in vm2.
Attackers can target a specific entry point like __proto__ over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 10.0/10.
What to do: upgrade vm2 to 3.11.8 or later.
If unsure, ask your IT team or search "vm2 CVE-2026-92955" on the vendor's site.

CVE-2026-92955 (vm2) — CWE-913 / CVSS v3 10.0
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: __proto__ / console._stdout / console._stderr / NodeVM
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-913) exists in vm2. Attackers reach the vulnerable code path via __proto__ without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of vm2. Attack surface: __proto__ / console._stdout / console._stderr / NodeVM.

🔥 Severity

Severity: Critical (CVSS 10.0/10). Successful exploitation can lead to full system takeover.

🔧 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

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