by Kastro
Paper/Archive/CVE-2026-25586

CVE-2026-25586

nyariv SandboxJS — SandboxJS has a Sandbox Escape via Prototype Whitelist Bypass and Host Prototype Pollution

EPSS 0.7%public exploitCVSS 10.0
critical.is priorityof 100
51
CVSS 10.0 (CNA)10.0 / 10 × 3030.0Not in CISA KEV+300.0EPSS percentile 53.3.533 × 2010.7Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
SandboxJS< 0.8.29–CNA

Scores by source

GitHub_M (CNA)10.0CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: total

References

exploitgithub.com/nyariv/SandboxJS/security/advisories/GHSA-jjpw-65fv-8g48refgithub.com/nyariv/SandboxJS/commit/67cb186c41c78c51464f70405504e8ef0a6e43c3