CVE-2026-25881
@nyariv/sandboxjs has host prototype pollution from sandbox via array intermediary (sandbox escape)
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
- nyariv · SandboxJS
- CVSS v3.1 NVD
- 10.0 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - CVSS v3.1 GITHUB
- 9.0 CRITICAL
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - EPSS
- 0.73% chance of exploitation in the next 30 days, 53rd percentile
- Published
- 2026-02-09
- Updated
- 2026-02-10
Proof-of-concept exploits (1)
Security advisories
- nyariv/SandboxJS/security/advisories/GHSA-ww7g-4gwx-m7wj
- nyariv/SandboxJS/commit/f369f8db26649f212a6a9a2e7a1624cb2f705b53