DEBIAN-CVE-2021-4189

Advisory lineage Upstream: 1 Downstream: 4
Upstream
CVE-2021-4189
Published: 24 Aug 2022, 16:15
Last modified:28 Apr 2026, 20:23

Vulnerability Summary

Overall Risk (default)
low
21/100
CVSS Score
5.3 MEDIUM
3.1 (osv_debian)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

24 Aug 2022, 16:15
Published
Vulnerability first disclosed
28 Apr 2026, 20:23
Last Modified
Vulnerability information updated

Description

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 ports, which otherwise would not have been possible.

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected Systems

  • debian•pypy3

    < 7.3.5+dfsg-2 | < 7.3.5+dfsg-2 | < 7.3.5+dfsg-2 | < 7.3.5+dfsg-2

  • debian•python2.7

    all

  • debian•python3.9

    < 3.9.2-1+deb11u2

References (1)