CVE-2026-34208

critical

SandboxJS is a JavaScript sandboxing library.

Vendor / product: Nyariv — sandboxjs

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

10.0

10.0 (CVSS v3.1)

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Severity source: NVD CVSS v3.1 (nvd@nist.gov)

Timeline (UTC)

Published: 2026-04-06 16:16

Modified: 2026-10-26 22:10

NVD status: Analyzed

Last synced 3 days ago

Verified against the source API 2026-10-27 07:07 UTC

Exploitation

Not listed in CISA KEV (as of last catalog sync)

Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

nyariv / sandboxjs <0.8.36

Weakness classification (CWE)

CWE-693 CWE-915

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

Vendor advisory: https://github.com/nyariv/SandboxJS/security/advisories/GHSA-2gg9-6p7w-6cpj

References

https://github.com/nyariv/SandboxJS/security/advisories/GHSA-2gg9-6p7w-6cpj security-advisories@github.com

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 07:07 UTC · record ↗

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