GHSA-cf66-xwfp-gvc4
HIGHMissing Origin Validation in webpack-dev-server
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
webpack-dev-servernpmDescription
Versions of webpack-dev-server before 3.1.10 are missing origin validation on the websocket server. This vulnerability allows a remote attacker to steal a developer's source code because the origin of requests to the websocket server that is used for Hot Module Replacement (HMR) are not validated.
Recommendation
For webpack-dev-server update to version 3.1.11 or later.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | webpack-dev-server | all versions | 3.1.11 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for webpack-dev-server. 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 webpack-dev-server to 3.1.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cf66-xwfp-gvc4 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 GHSA-cf66-xwfp-gvc4 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 GHSA-cf66-xwfp-gvc4. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-cf66-xwfp-gvc4 in your dependencies?
O3 detects GHSA-cf66-xwfp-gvc4 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.