CVE-2026-34208
SandboxJS: Sandbox integrity escape
10.0CVSSCRITICAL
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 Vector Breakdown
Exploitability
AV:NAttack VectorNetwork
AC:LAttack ComplexityLow
PR:NPrivileges RequiredNone
UI:NUser InteractionNone
Scope
S:CScopeChanged
Impact
C:HConfidentialityHigh
I:HIntegrityHigh
A:LAvailabilityLow
Weaknesses
Affected Products
Exploitability
Official Patch Available
References
Timeline
Published
Apr 6, 2026
Last Updated
Apr 9, 2026
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