CVE-2009-5013
CVE-2009-5013 is a CWE-399 vulnerability in pyftpdlib. O3 Security confirms whether CVE-2009-5013 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Uncontrolled Resource Consumption in pyftpdlib
Blast Radius
pyftpdlibReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Memory leak in the on_dtp_close function in ftpserver.py in pyftpdlib before 0.5.2 allows remote authenticated users to cause a denial of service (memory consumption) by sending a QUIT command during a data transfer.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pyftpdlib | all versions | 0.5.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyftpdlib. 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 pyftpdlib to 0.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2009-5013 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-2009-5013 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-2009-5013. 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-2009-5013 in your dependencies?
O3 detects CVE-2009-5013 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.