CVE-2026-53633
CRITICALVitest: Exposed Browser Mode API Can Proxy CDP and Overwrite Config Files, Leading to RCE
Blast Radius
@vitest/browser📦@vitest/browser📦@vitest/browser📦vite-plusReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Vitest is a testing framework powered by Vite. From 3.0.0 until 3.2.5, 4.1.8, and 5.0.0-beta.4, Vitest Browser Mode exposed a cdp() API that forwarded raw Chrome DevTools Protocol methods without being gated by allowWrite or allowExec, allowing a remote client with exposed browser API metadata to use CDP Page.setDownloadBehavior and Runtime.evaluate to overwrite vite.config.ts and execute attacker-controlled Node.js code. This issue is fixed in versions 3.2.5, 4.1.8, and 5.0.0-beta.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @vitest/browser | ≥ 5.0.0-beta.0&&< 5.0.0-beta.4 | 5.0.0-beta.4 |
| 📦npm | @vitest/browser | ≥ 4.0.0&&< 4.1.8 | 4.1.8 |
| 📦npm | @vitest/browser | ≥ 3.0.0&&< 3.2.5 | 3.2.5 |
| 📦npm | vite-plus | all versions | 0.1.24 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @vitest/browser. 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 @vitest/browser to 5.0.0-beta.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-53633 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-2026-53633 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-2026-53633. 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-2026-53633 in your dependencies?
O3 detects CVE-2026-53633 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.