CVE-2026-25881 CRITICAL

CVE-2026-25881: @nyariv/sandboxjs has host prototype pollution from sandbox via array intermediary (sandbox escape)

Vendor Nyariv
Product SandboxJS
Weakness CWE-1321
Published February 9, 2026
Last update February 10, 2026

CVSS base score

9.1/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:H/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 0.8.31, a sandbox escape vulnerability allows sandboxed code to mutate host built-in prototypes by laundering the isGlobal protection flag through array literal intermediaries. When a global prototype reference (e.g., Map.prototype, Set.prototype) is placed into an array and retrieved, the isGlobal taint is stripped, permitting direct prototype mutation from within the sandbox. This results in persistent host-side prototype pollution and may enable RCE in applications that use polluted properties in sensitive sinks (example gadget: execSync(obj.cmd)). This vulnerability is fixed in 0.8.31.

Key dates

02Disclosure timeline

February 9, 2026 CVE published
February 10, 2026 Record updated