Vulnerability · Published Apr 6, 2026 · Assigned by GitHub_M
CVE-2026-34217SandboxJS has a Sandbox Escape via Prop Object Leak in New Handler
Medium 6.9
In plain English
A medium-severity security flaw in SandboxJS from nyariv. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @nyariv/sandboxjs | 0.8.36 | GHSA-hg73-4w7g-q96w |
Affected products (as reported)
Weakness: CWE-668 · 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
References
- https://github.com/nyariv/SandboxJS/security/advisories/GHSA-hg73-4w7g-q96w x_refsource_CONFIRM