CVE-2021-4189

MEDIUM

Python - Info Disclosure

Title source: llm

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.

References (10)

[Third Party Advisory] https://access.redhat.com/security/cve/CVE-2021-4189

[Patch, Vendor Advisory] https://bugs.python.org/issue43285

[Issue Tracking, Patch, Third Party Advisory] https://bugzilla.redhat.com/show_bug.cgi?id=2036020

[Patch, Third Party Advisory] https://github.com/python/cpython/commit/0ab152c6b5d95caa2dc1a30fa96e10258b5f188e

View Patch ZIP pw:eip

[Mailing List] https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html

[Mailing List] https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html

[Patch, Third Party Advisory] https://python-security.readthedocs.io/vuln/ftplib-pasv.html

[Third Party Advisory] https://security-tracker.debian.org/tracker/CVE-2021-4189

[Third Party Advisory] https://security.netapp.com/advisory/ntap-20221104-0004/

[Mailing List] https://lists.debian.org/debian-lts-announce/2024/12/msg00000.html

Scores

CVSS v3 5.3

EPSS 0.0106

EPSS Percentile 77.3%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Classification

CWE

CWE-252

Status published

Affected Products (7)

python/python < 3.6.14

python/python

debian/debian_linux

debian/debian_linux

redhat/software_collections

redhat/enterprise_linux

netapp/ontap_select_deploy_administration_utility

Timeline

Published Aug 24, 2022

Tracked Since Feb 18, 2026