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CVE-2009-5012 pyftpdlib

CVE-2009-5012 is a CWE-264 vulnerability in pyftpdlib. A fix is available for pyftpdlib — see the affected versions and patch details below.

Improper Access Control in pyftpdlib

Also known asGHSA-h4g7-8m7r-87r9PYSEC-2010-9
Published
Oct 19, 2010
Updated
Apr 10, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.0%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs61th percentile — riskier than 61% of all scored CVEsHighest risk

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.

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

ftpserver.py in pyftpdlib before 0.5.2 does not require the l permission for the MLST command, which allows remote authenticated users to bypass intended access restrictions and list the root directory via an FTP session.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIpyftpdliball versions0.5.2pip install --upgrade 'pyftpdlib==0.5.2'

Detection & mitigation playbook

Open-source dependency
  1. 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.

  2. Fix

    Update pyftpdlib to 0.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2009-5012 is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2009-5012 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2009-5012. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

ftpserver.py in pyftpdlib before 0.5.2 does not require the l permission for the MLST command, which allows remote authenticated users to bypass intended access restrictions and list the root directory via an FTP session.
O3 Security · Impact-Aware SCA

Is CVE-2009-5012 in your dependencies?

O3 Security finds CVE-2009-5012 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

CVE-2009-5012: pyftpdlib | O3 Security