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Description

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.

PUBLISHED Reserved 2026-02-06 | Published 2026-02-09 | Updated 2026-02-09 | Assigner GitHub_M




CRITICAL: 9.1CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Problem types

CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

Product status

< 0.8.31
affected

References

github.com/...dboxJS/security/advisories/GHSA-ww7g-4gwx-m7wj

github.com/...ommit/f369f8db26649f212a6a9a2e7a1624cb2f705b53

cve.org (CVE-2026-25881)

nvd.nist.gov (CVE-2026-25881)

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