CVE-2026-34208: critical vulnerability in nyariv SandboxJS
SandboxJS: Sandbox integrity escape
Published
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28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 10epss 0.6%
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:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L
Affected products
nyariv · SandboxJSRelated CVEs — nyariv SandboxJS
In the same product, most dangerous first.
CVE-2026-23830CRITICALSandboxJS has Sandbox Escape via Unprotected AsyncFunction ConstructorEPSS 1.2%CVE-2026-25142CRITICALSandboxJS Prototype Pollution -> Sandbox Escape -> RCEEPSS 1.2%CVE-2026-25520CRITICALSandboxJS has a Sandbox EscapeEPSS 0.9%CVE-2026-25587CRITICALSandboxJS has a Sandbox EscapeEPSS 0.7%CVE-2026-25586CRITICALSandboxJS has a Sandbox Escape via Prototype Whitelist Bypass and Host Prototype PollutionEPSS 0.7%CVE-2026-25881CRITICAL@nyariv/sandboxjs has host prototype pollution from sandbox via array intermediary (sandbox escape)EPSS 0.6%