Critical 10.0Published Feb 6, 2026

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

Updated under an hour ago (Oct 27, 2026, 1:40 AM ET)

Does this affect you?

It affects nyariv SandboxJS. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for nyariv SandboxJS

Exploited in the last 30 days

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.

CVSS: 10.0 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Weakness (CWE): CWE-74
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Feb 6, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

nyariv SandboxJS nyariv:sandboxjs (from the name)	before 0.8.29	CNA record
nyariv sandboxjs nyariv:sandboxjs	before 0.8.29	NVD

References

References

https://github.com/nyariv/SandboxJS/security/advisories/GHSA-jjpw-65fv-8g48	x-refsource-confirm, exploit, vendor-advisory
https://github.com/nyariv/SandboxJS/commit/67cb186c41c78c51464f70405504e8ef0a6e43c3	x-refsource-misc, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.