UpHeron
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Servers and applications

CVE-2021-4189

A flaw was found in Python, specifically in the FTP (File Transfer Protocol) client library in PASV (passive) mode. The issue is how the FTP client trusts the host from the PASV response by default. This flaw allows an attacker to set up a malicious FTP server that can trick FTP clients into connecting back to a given IP address and port. This vulnerability could lead to FTP client scanning…

Severity
Medium 5.3
Published
24 Aug 2022
Last changed
14 Oct 2026
Added to UpHeron
21 Oct 2026
Fixed in
3.6.14, 3.7.11, 3.8.9, 3.9.3
Sources
NVD

Affected software

SoftwareAffected versions
PythonServers and applications · cpe:a:python:python
  • From 3.6.0 before 3.6.14
  • From 3.7.0 before 3.7.11
  • From 3.8.0 before 3.8.9
  • From 3.9.0 before 3.9.3
  • Version 3.10.0

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2021-4189
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2021-4189