CVE-2026-25586

SandboxJS has a Sandbox Escape via Prototype Whitelist Bypass and Host Prototype Pollution

Published Feb 6, 2026 CVSS 3.1 · 10 Critical EPSS < 1% KEV · Not listed
Description
SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, a sandbox escape is possible by shadowing hasOwnProperty on a sandbox object, which disables prototype whitelist enforcement in the property-access path. This permits direct access to __proto__ and other blocked prototype properties, enabling host Object.prototype pollution and persistent cross-sandbox impact. This vulnerability is fixed in 0.8.29.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-jjpw-65fv-8g48 @nyariv/sandboxjs has Sandbox Escape via Prototype Whitelist Bypass and Host Prototype Pollution
History
Type Values Removed Values Added
CPEs cpe:2.3:a:nyariv:sandboxjs:*:*:*:*:*:node.js:*:*
Type Values Removed Values Added
First Time appeared Nyariv
Nyariv sandboxjs
Vendors & Products Nyariv
Nyariv sandboxjs
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, a sandbox escape is possible by shadowing hasOwnProperty on a sandbox object, which disables prototype whitelist enforcement in the property-access path. This permits direct access to __proto__ and other blocked prototype properties, enabling host Object.prototype pollution and persistent cross-sandbox impact. This vulnerability is fixed in 0.8.29.
Title SandboxJS has a Sandbox Escape via Prototype Whitelist Bypass and Host Prototype Pollution
Weaknesses CWE-74
References
Metrics cvssV3_1

{'score': 10, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Feb 6, 2026, 8:17 PM
Reserved
Feb 3, 2026, 1:02 AM
Status
Analyzed
Published
Feb 6, 2026, 8:16 PM
Modified
Jun 17, 2026, 10:24 AM