Vulnerability-Lookup

CVE-2026-23830 (GCVE-0-2026-23830)

Vulnerability from cvelistv5 – Published: 2026-01-27 23:32 – Updated: 2026-01-28 15:09

Title

SandboxJS has Sandbox Escape via Unprotected AsyncFunction Constructor

Summary

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.

Severity

10 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

SSVC

Exploitation: poc Automatable: yes Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-94 - Improper Control of Generation of Code ('Code Injection')
CWE-693 - Protection Mechanism Failure
CWE-913 - Improper Control of Dynamically-Managed Code Resources

Assigner

GitHub_M

References

2 references

URL	Tags
https://github.com/nyariv/SandboxJS/security/advi…	x_refsource_CONFIRM
https://github.com/nyariv/SandboxJS/commit/345aee…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
nyariv	SandboxJS	Affected: < 0.8.26

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-23830

Vulnerability from fkie_nvd - Published: 2026-01-28 00:15 - Updated: 2026-02-12 20:47

Severity

10.0 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/nyariv/SandboxJS/commit/345aee6566e47979dee5c337b925b141e7f78ccd	Patch
	security-advisories@github.com	https://github.com/nyariv/SandboxJS/security/advisories/GHSA-wxhw-j4hc-fmq6	Exploit, Vendor Advisory

Impacted products

	Vendor	Product	Version
	nyariv	sandboxjs	*

JSON

To clipboard

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:nyariv:sandboxjs:*:*:*:*:*:node.js:*:*",
              "matchCriteriaId": "39569A92-6C8F-4E00-8280-F8AA92EA4150",
              "versionEndExcluding": "0.8.26",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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 () =\u003e {}).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."
    },
    {
      "lang": "es",
      "value": "SandboxJS es una librer\u00eda de sandboxing de JavaScript. Las versiones anteriores a la 0.8.26 tienen una vulnerabilidad de escape de sandbox debido a que `AsyncFunction` no est\u00e1 aislada en `SandboxFunction`. La librer\u00eda intenta aplicar un sandbox a la ejecuci\u00f3n de c\u00f3digo reemplazando el constructor global `Function` con una versi\u00f3n segura y con sandbox (`SandboxFunction`). Esto se maneja en `utils.ts` mapeando `Function` a `sandboxFunction` dentro de un mapa utilizado para b\u00fasquedas. Sin embargo, antes de la versi\u00f3n 0.8.26, la librer\u00eda no inclu\u00eda mapeos para `AsyncFunction`, `GeneratorFunction` y `AsyncGeneratorFunction`. Estos constructores no son propiedades globales, pero se puede acceder a ellos a trav\u00e9s de la propiedad `.constructor` de una instancia (por ejemplo, `(async () =\u0026gt; {}).constructor`). En `executor.ts`, se maneja el acceso a propiedades. Cuando el c\u00f3digo que se ejecuta dentro del sandbox accede a `.constructor` en una funci\u00f3n as\u00edncrona (que el sandbox permite crear), el `executor` recupera el valor de la propiedad. Dado que `AsyncFunction` no estaba en el mapa de reemplazo seguro, el `executor` devuelve el constructor `AsyncFunction` nativo real del host. Los constructores para funciones en JavaScript (como `Function`, `AsyncFunction`) crean funciones que se ejecutan en el \u00e1mbito global. Al obtener el constructor `AsyncFunction` del host, un atacante puede crear una nueva funci\u00f3n as\u00edncrona que se ejecuta completamente fuera del contexto del sandbox, eludiendo todas las restricciones y obteniendo acceso total al entorno del host (ejecuci\u00f3n remota de c\u00f3digo). La versi\u00f3n 0.8.26 corrige esta vulnerabilidad."
    }
  ],
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  "lastModified": "2026-02-12T20:47:16.640",
  "metrics": {
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  "vulnStatus": "Analyzed",
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      "source": "security-advisories@github.com",
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}

GHSA-WXHW-J4HC-FMQ6

Vulnerability from github – Published: 2026-01-27 19:55 – Updated: 2026-01-29 03:43

Summary

SandboxJS has Sandbox Escape via Unprotected AsyncFunction Constructor

Details

Summary

A sandbox escape vulnerability due to AsyncFunction not being isolated in SandboxFunction

Details

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, 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).

PoC

const sandbox = require('@nyariv/sandboxjs');
const s = new sandbox.default();

const payload = `
    const af = async () => {};
    // .constructor returns the host AsyncFunction constructor because it's not intercepted
    const AsyncConstructor = af.constructor;
    console.log("AsyncConstructor name:", AsyncConstructor.name);

    // Create a function that executes outside the sandbox
    const func = AsyncConstructor("return process.mainModule.require('child_process').execSync('id').toString()");

    // Execute RCE
    const p = func();
    p.then(proc => {
        console.log(proc);
    });
`;

try {
    s.compile(payload)().run();
} catch (e) {
    console.error("Bypass failed:", e.message);
}

Run above script in nodejs. If you run it in browser, change the AsyncConstructor argument by returning window object.

Impact

A Remote Code Execution, attacker may be able to run an arbitrary code.

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

JSON

To clipboard

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      "package": {
        "ecosystem": "npm",
        "name": "@nyariv/sandboxjs"
      },
      "ranges": [
        {
          "events": [
            {
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          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-23830"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-693",
      "CWE-913",
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-01-27T19:55:11Z",
    "nvd_published_at": "2026-01-28T00:15:50Z",
    "severity": "CRITICAL"
  },
  "details": "### Summary\nA sandbox escape vulnerability due to `AsyncFunction` not being isolated in `SandboxFunction`\n\n### Details\n\nThe 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.\n\nHowever, 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 () =\u003e {}).constructor`).\n\nIn `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.\n\nConstructors 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).\n\n### PoC\n\n```js\nconst sandbox = require(\u0027@nyariv/sandboxjs\u0027);\nconst s = new sandbox.default();\n\nconst payload = `\n    const af = async () =\u003e {};\n    // .constructor returns the host AsyncFunction constructor because it\u0027s not intercepted\n    const AsyncConstructor = af.constructor;\n    console.log(\"AsyncConstructor name:\", AsyncConstructor.name);\n    \n    // Create a function that executes outside the sandbox\n    const func = AsyncConstructor(\"return process.mainModule.require(\u0027child_process\u0027).execSync(\u0027id\u0027).toString()\");\n    \n    // Execute RCE\n    const p = func();\n    p.then(proc =\u003e {\n        console.log(proc);\n    });\n`;\n\ntry {\n    s.compile(payload)().run();\n} catch (e) {\n    console.error(\"Bypass failed:\", e.message);\n}\n```\n\nRun above script in nodejs. If you run it in browser, change the `AsyncConstructor` argument by returning `window` object. \n\n### Impact\n\nA Remote Code Execution, attacker may be able to run an arbitrary code.",
  "id": "GHSA-wxhw-j4hc-fmq6",
  "modified": "2026-01-29T03:43:42Z",
  "published": "2026-01-27T19:55:11Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nyariv/SandboxJS/security/advisories/GHSA-wxhw-j4hc-fmq6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23830"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nyariv/SandboxJS/commit/345aee6566e47979dee5c337b925b141e7f78ccd"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nyariv/SandboxJS"
    }
  ],
  "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 has Sandbox Escape via Unprotected AsyncFunction Constructor"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-23830 (GCVE-0-2026-23830)

FKIE_CVE-2026-23830

GHSA-WXHW-J4HC-FMQ6

Summary

Details

PoC

Impact

Tags

Sightings

Nomenclature