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CVE-2026-100722 medium CVSS 6.8

Vulnerability in vm2 (CVE-2026-100722)

Summary

Vulnerability in vm2 (CVE-2026-100722). Risk of unauthorized operations or information disclosure. Exploitable via VM.run. Mitigation: upgrade to 3.12.2 or later.

Original description

The description as published by the source.

Summary

An untrusted script run by VM.run can construct an embedder-exposed host function that returns a rejected native Promise and ignore the result. The sandbox-to-host construct trap forwards that Promise without applying the host-side rejection handling already used by the neighboring apply trap, so Node's strict unhandled-rejection policy terminates the host process.

Technical Details

The precondition is an application-supplied constructable host function in the VM sandbox whose constructor body returns a native rejected Promise. In JavaScript, an object explicitly returned by a constructor replaces the newly allocated instance, so new HostReject() produces that Promise.

VM.run executes the attacker-controlled source. For an ordinary host-function call, BaseHandler.apply invokes the host function, calls markHostPromiseHandled(ret), and then wraps the result. The adjacent BaseHandler.construct path instead calls Reflect.construct and returns thisFromOtherWithFactory(...) without calling the same sanitizer. The rejected host Promise therefore crosses the bridge still unhandled. With Node's strict unhandled-rejection behavior, the rejection is promoted to an uncaught exception and kills the host process.

The shortest path is VM.run → the sandbox bridge → BaseHandler.construct. The control changes only the guest expression: it attaches .catch(function () {}) to the constructed Promise before ignoring it. The host function, VM configurati…

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-2026-100722 has been found in vm2.
Attackers can target a specific entry point like VM.run over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.8/10.
What to do: upgrade vm2 to 3.12.2 or later.
If unsure, ask your IT team or search "vm2 CVE-2026-100722" on the vendor's site.

CVE-2026-100722 (vm2) — CWE-248 / CVSS v3 6.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: VM.run / construct / apply / BaseHandler.apply
Patched: 3.12.2 — 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-248) exists in vm2. Attackers reach the vulnerable code path via VM.run without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of vm2. Attack surface: VM.run / construct / apply / BaseHandler.apply.

🔥 Severity

Severity: Medium (CVSS 6.8/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 3.12.2.

🛡️ 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 3.12.2

    ステージング環境で 3.12.2 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":"3.12.2"}]}]

References

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