by Kastro
Paper/Archive/CVE-2026-25881

CVE-2026-25881

nyariv SandboxJS — @nyariv/sandboxjs has host prototype pollution from sandbox via array intermediary (sandbox escape)

EPSS 0.6%CVSS 10.0
critical.is priorityof 100
40
CVSS 10.0 (NVD)10.0 / 10 × 3030.0Not in CISA KEV+300.0EPSS percentile 49.9.499 × 2010.0No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
SandboxJS< 0.8.31–CNA

Scores by source

NVD10.0CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
GitHub_M (CNA)9.1CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

refgithub.com/nyariv/SandboxJS/security/advisories/GHSA-ww7g-4gwx-m7wjrefgithub.com/nyariv/SandboxJS/commit/f369f8db26649f212a6a9a2e7a1624cb2f705b53