Vulnerability Description
SandboxJS is a JavaScript sandboxing library. Prior to 0.8.36, SandboxJS blocks direct assignment to global objects (for example Math.random = ...), but this protection can be bypassed through an exposed callable constructor path: this.constructor.call(target, attackerObject). Because this.constructor resolves to the internal SandboxGlobal function and Function.prototype.call is allowed, attacker code can write arbitrary properties into host global objects and persist those mutations across sandbox instances in the same process. This vulnerability is fixed in 0.8.36.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nyariv | Sandboxjs | < 0.8.36 |
Related Weaknesses (CWE)
References
- https://github.com/nyariv/SandboxJS/security/advisories/GHSA-2gg9-6p7w-6cpjExploitVendor Advisory
FAQ
What is CVE-2026-34208?
CVE-2026-34208 is a vulnerability with a CVSS score of 10.0 (CRITICAL). SandboxJS is a JavaScript sandboxing library. Prior to 0.8.36, SandboxJS blocks direct assignment to global objects (for example Math.random = ...), but this protection can be bypassed through an expo...
How severe is CVE-2026-34208?
CVE-2026-34208 has been rated CRITICAL with a CVSS base score of 10.0/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-34208?
Check the references section above for vendor advisories and patch information. Affected products include: Nyariv Sandboxjs.