Vulnerability in vm2 (CVE-2026-47683)
Summary
Vulnerability in vm2 (CVE-2026-47683). Risk of unauthorized operations or information disclosure. Exploitable via bufferAllocLimit. Mitigation: upgrade to 3.11.6 or later.
Original description
The description as published by the source.
Summary
vm2 bufferAllocLimit cap bypassed by Buffer.concat and Buffer.from arrayLike
The bufferAllocLimit option introduced in 3.11.0 (GHSA-6785-pvv7-mvg7) caps host-side Buffer allocations driven by sandbox code, the way embedders opt into timeout. The cap wraps Buffer.alloc, Buffer.allocUnsafe, Buffer.allocUnsafeSlow, and the deprecated Buffer(N) / new Buffer(N) forms. Two other API paths reach the same host C++ allocator with an attacker-controlled size and are not capped: Buffer.concat(list, totalLength) and Buffer.from(arrayLike) with a fake length. Sandbox code can use either to allocate an arbitrary number of host external bytes in a single call, defeating the explicit DoS mitigation the embedder configured.
Details
lib/setup-sandbox.js installs checkBufferAllocLimit at every wrapped entry to host Buffer allocation:
alloc()atlib/setup-sandbox.js:474and theconnect(alloc, host.Buffer.alloc)at line 480.allocUnsafe()at line 488 andconnect(allocUnsafe, host.Buffer.allocUnsafe)at line 496.allocUnsafeSlow()at line 504 andconnect(allocUnsafeSlow, host.Buffer.allocUnsafeSlow)at line 510.BufferHandler.applyat line 424 andBufferHandler.constructat line 433 for the deprecatedBuffer(N)/new Buffer(N)numeric-first-arg paths.
Buffer.concat is not wrapped. The sandbox-visible Buffer.concat is therefore the bridge proxy of the host Buffer.concat, which calls into Node's `Buffer.allocUnsafe(total…
Source: GitHub Security Advisories (Global) 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-2026-47683 has been found in vm2.
Attackers can target a specific entry point like bufferAllocLimit over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade vm2 to 3.11.6 or later.
If unsure, ask your IT team or search "vm2 CVE-2026-47683" on the vendor's site.
CVE-2026-47683 (vm2) — CWE-770
Attack surface: bufferAllocLimit / timeout / Buffer.alloc / Buffer.allocUnsafe
Patched: 3.11.6 — 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.
A vulnerability (CWE-770) exists in vm2. Attackers reach the vulnerable code path via bufferAllocLimit.
Check the vendor advisory for the affected versions of vm2. Attack surface: bufferAllocLimit / timeout / Buffer.alloc / Buffer.allocUnsafe.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 3.11.6.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
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
-
1Identify 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。 -
2Apply patch patch
Upgrade vm2 to 3.11.6ステージング環境で 3.11.6 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。
-
3Post-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
References
- package github.com
- web github.com
- web github.com
- web github.com
- web security-advisories@github.com