CVE-2026-34211: Nyariv Sandboxjs

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.36, the @nyariv/sandboxjs parser contains unbounded recursion in the restOfExp function and the lispify/lispifyExpr call chain. An attacker can crash any Node.js process that parses untrusted input by supplying deeply nested expressions (e.g., ~2000 nested parentheses), causing a RangeError: Maximum call stack size exceeded that terminates the process. This vulnerability is fixed in 0.8.36.

Affected products

• Nyariv Sandboxjs: before 0.8.36 (fixed in 0.8.36)

Published 2026-04-06. Last modified 2026-06-17.