CVE-2026-34217 MEDIUM

CVE-2026-34217: SandboxJS has a Sandbox Escape via Prop Object Leak in New Handler

Vendor Nyariv
Product SandboxJS
Weakness CWE-668
Published April 6, 2026
Last update April 6, 2026

CVSS base score

6.9/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.36, a scope modification vulnerability exists in @nyariv/sandboxjs. The vulnerability allows untrusted sandboxed code to leak internal interpreter objects through the new operator, exposing sandbox scope objects in the scope hierarchy to untrusted code; an unexpected and undesired exploit. While this could allow modifying scopes inside the sandbox, code evaluation remains sandboxed and prototypes remain protected throughout the execution. This vulnerability is fixed in 0.8.36.

Key dates

02Disclosure timeline

April 6, 2026 CVE published
April 6, 2026 Record updated