How severe is CVE-2009-5011?

No CVSS score has been assigned to CVE-2009-5011 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2009-5011?

CVE-2009-5011 affects the following packages: pyftpdlib (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2009-5011?

Update pyftpdlib to 0.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2009-5011 is resolved across your whole dependency graph.

How do I detect CVE-2009-5011 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyftpdlib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2009-5011 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2009-5011 actively exploited in the wild?

No public exploit code has been indexed for CVE-2009-5011 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2009-5011?

CVE-2009-5011 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 60th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2009-5011?

CVE-2009-5011 is classified as CWE-362 (CWE-362). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2009-5011 published, and has it been updated?

CVE-2009-5011 was published on October 19, 2010 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2009-5011 — pyftpdlib

CVE-2009-5011 is a CWE-362 vulnerability in pyftpdlib. A fix is available for pyftpdlib — see the affected versions and patch details below.

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') in pyftpdlib

Also known asGHSA-62xg-239j-vxg7PYSEC-2010-8

Published

Oct 19, 2010

Updated

Apr 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 28, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs60th percentile — riskier than 60% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍pyftpdlib

Real-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

Race condition in the FTPHandler class in ftpserver.py in pyftpdlib before 0.5.2 allows remote attackers to cause a denial of service (daemon outage) by establishing and then immediately closing a TCP connection, leading to the getpeername function having an ENOTCONN error, a different vulnerability than CVE-2010-3494.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`pyftpdlib`	all versions	0.5.2`pip install --upgrade 'pyftpdlib==0.5.2'`

Affected Products

1 product · 7 configurations

Application

pyftpdlibg.rodola

≤ 0.5.1

6 versions

0.10.1.10.2.00.3.00.4.00.5.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyftpdlib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pyftpdlib to 0.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2009-5011 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.