What’s Vulnerable › Vulnerabilities

CVE-2025-34146: nyariv sandboxjs 0.8.23 Prototype Pollution Sandbox Escape DoS

• Severity: high (CVSS 7.0 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-07-31 · updated 2026-10-08
• Weakness: CWE-1321

Description

A prototype pollution vulnerability exists in @nyariv/sandboxjs versions <= 0.8.23, allowing attackers to inject arbitrary properties into Object.prototype via crafted JavaScript code. This can result in a denial-of-service (DoS) condition or, under certain conditions, escape the sandboxed environment intended to restrict code execution. The vulnerability stems from insufficient prototype access checks in the sandbox’s executor logic, particularly in the handling of JavaScript function objects returned.

Affected products

• nyariv SandboxJS: through 0.8.23

References

• https://gist.github.com/Hagrid29/9df27829a491080f923c4f6b8518d7e3
• https://github.com/nyariv/SandboxJS/issues/31
• https://www.npmjs.com/package/@nyariv/sandboxjs
• https://www.vulncheck.com/advisories/nyariv-sandboxjs-prototype-pollution-sandbox-escape-dos

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