CVE-2026-25586 — SandboxJS has a Sandbox Escape via Prototype Whitelist Bypass and Host Prototype Pollution
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 e…
Published: 2026-02-06 · CVSS: 10.0 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7