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Fencer Intel
medium 4.3

CVE-2009-5011 json

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

published 16y ago modified 4mo ago also GHSA-62xg-239j-vxg7 , PYSEC-2010-8 , EUVD-2010-0026

cvss
4.3
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 60%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi pyftpdlib 0.5.2
  • python-pyftpdlib Debian 14, Debian 13, Debian 12 0.5.2-1

debian advisories DEBIAN-CVE-2009-5011

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2009-5011 updated cvss 5.0

pyftpdlib: Race condition in the FTPHandler class

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.92% chance of exploitation in the next 30 days, higher than 60% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

Affected packages

ecosystem package affected fixed in
pypi pyftpdlib
<0.5.2
0.5.2

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.