CVE-2026-26954
CRITICALCVE-2026-26954 is a critical-severity (CVSS 10) Code Injection vulnerability in @nyariv/sandboxjs. O3 Security confirms whether CVE-2026-26954 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
SandboxJS has a Sandbox Escape
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
@nyariv/sandboxjsnpmDescription
SandboxJS is a JavaScript sandboxing library. Prior to 0.8.34, it is possible to obtain arrays containing Function, which allows escaping the sandbox. Given an array containing Function, and Object.fromEntries, it is possible to construct {[p]: Function} where p is any constructible property. This vulnerability is fixed in 0.8.34.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @nyariv/sandboxjs | all versions | 0.8.34 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @nyariv/sandboxjs. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @nyariv/sandboxjs to 0.8.34 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-26954 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-26954 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-26954. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-26954 in your dependencies?
O3 detects CVE-2026-26954 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.