GHSA-5f4x-hwv2-w9w2
CRITICALrejetto HFS vulnerable to OS Command Execution by remote authenticated users
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
hfsReal-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
rejetto HFS (aka HTTP File Server) 3 before 0.52.10 on Linux, UNIX, and macOS allows OS command execution by remote authenticated users (if they have Upload permissions). This occurs because a shell is used to execute df (i.e., with execSync instead of spawnSync in child_process in Node.js).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | hfs | all versions | 0.52.10 |
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 hfs. 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 hfs to 0.52.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5f4x-hwv2-w9w2 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-5f4x-hwv2-w9w2 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-5f4x-hwv2-w9w2. 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-5f4x-hwv2-w9w2 in your dependencies?
O3 detects GHSA-5f4x-hwv2-w9w2 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.