CVE-2026-25586 CRITICAL

CVE-2026-25586: SandboxJS has a Sandbox Escape via Prototype Whitelist Bypass and Host Prototype Pollution

Vendor Nyariv
Product SandboxJS
Weakness CWE-74
Published February 6, 2026
Last update February 6, 2026
View on NVD All CVEs

CVSS base score

10.0/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

February 6, 2026 CVE published
February 6, 2026 Record updated