CVE-2026-25520: Nyariv Sandboxjs

Critical severity, CVSS 10.0. EPSS: 0.9% chance of exploitation in the next 30 days.

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, The return values of functions aren't wrapped. Object.values/Object.entries can be used to get an Array containing the host's Function constructor, by using Array.prototype.at you can obtain the hosts Function constructor, which can be used to execute arbitrary code outside of the sandbox. This vulnerability is fixed in 0.8.29.

Affected products

• Nyariv Sandboxjs: before 0.8.29 (fixed in 0.8.29)

Published 2026-02-06. Last modified 2026-06-17.