SandboxJS has Sandbox Escape via Unprotected AsyncFunction Constructor_CVE-2026-23830

{
    "lastseen": "",
    "description": "SandboxJS is a JavaScript sandboxing library. Versions prior to 0.8.26 have a sandbox escape vulnerability due to `AsyncFunction` not being isolated in `SandboxFunction`. The library attempts to sandbox code execution by replacing the global `Function` constructor with a safe, sandboxed version (`SandboxFunction`). This is handled in `utils.ts` by mapping `Function` to `sandboxFunction` within a map used for lookups. However, before version 0.8.26, the library did not include mappings for `AsyncFunction`, `GeneratorFunction`, and `AsyncGeneratorFunction`. These constructors are not global properties but can be accessed via the `.constructor` property of an instance (e.g., `(async () => {}).constructor`). In `executor.ts`, property access is handled. When code running inside the sandbox accesses `.constructor` on an async function (which the sandbox allows creating), the `executor` retrieves the property value. Since `AsyncFunction` was not in the safe-replacement map, the `executor` returns the actual native host `AsyncFunction` constructor. Constructors for functions in JavaScript (like `Function`, `AsyncFunction`) create functions that execute in the global scope. By obtaining the host `AsyncFunction` constructor, an attacker can create a new async function that executes entirely outside the sandbox context, bypassing all restrictions and gaining full access to the host environment (Remote Code Execution). Version 0.8.26 patches this vulnerability.",
    "published": "2026-01-27T23:32:16.104Z",
    "modified": "2026-01-27T23:32:16.104Z",
    "type": "cve",
    "title": "SandboxJS has Sandbox Escape via Unprotected AsyncFunction Constructor",
    "source": "GitHub_M",
    "references": "https://github.com/nyariv/SandboxJS/security/advisories/GHSA-wxhw-j4hc-fmq6\nhttps://github.com/nyariv/SandboxJS/commit/345aee6566e47979dee5c337b925b141e7f78ccd",
    "id": "CVE-2026-23830",
    "bulletinFamily": "",
    "cwe": [
        "CWE-94",
        "CWE-693",
        "CWE-913"
    ],
    "cvelist": null,
    "sourceData": "nyariv SandboxJS < 0.8.26",
    "sourceHref": "",
    "cvss": {
        "score": 10,
        "severity": "CRITICAL",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
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        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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            "privilegesRequired": "",
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            "integrityImpact": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "SandboxJS",
    "version": "< 0.8.26",
    "vendor": "nyariv",
    "ai_description": "",
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    "ai_score": 0
}