CVE-2026-25586 | THREATINT

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.

PUBLISHED Reserved 2026-02-03 | Published 2026-02-06 | Updated 2026-02-06 | Assigner GitHub_M

CRITICAL: 10.0CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Problem types

CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Product status

< 0.8.29

affected

References

github.com/...dboxJS/security/advisories/GHSA-jjpw-65fv-8g48 exploit

github.com/...dboxJS/security/advisories/GHSA-jjpw-65fv-8g48

github.com/...ommit/67cb186c41c78c51464f70405504e8ef0a6e43c3

cve.org (CVE-2026-25586)

nvd.nist.gov (CVE-2026-25586)

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