Vulnerability · Published Jul 31, 2025 · Assigned by VulnCheck

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

High 7.0

In plain English

A high-severity prototype pollution in sandboxjs from nyariv. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)7.0High

Exploit odds (30 days)0.2%top 84.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	@nyariv/sandboxjs	0.8.24	GHSA-9qm3-6qrr-c76m

Affected products (as reported)

Vendor	Product	Versions
nyariv	sandboxjs	0 – through 0.8.23

Weakness: CWE-1321 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

References

https://gist.github.com/Hagrid29/9df27829a491080f923c4f6b8518d7e3 issue-tracking, exploit
https://github.com/nyariv/SandboxJS/issues/31 issue-tracking
https://www.npmjs.com/package/@nyariv/sandboxjs product
https://www.vulncheck.com/advisories/nyariv-sandboxjs-prototype-pollution-sandbox-escape-dos third-party-advisory