PyPi: Python

CVE-2021-4189

Safety vulnerability ID: 50765

This vulnerability was reviewed by experts

The information on this page was manually curated by our Cybersecurity Intelligence Team.

Created at Aug 24, 2022 Updated at Nov 29, 2024
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Advisory

Python 3.6.14, 3.7.11, 3.8.9 and 3.9.3 include a fix for CVE-2021-4189: 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.
https://python-security.readthedocs.io/vuln/ftplib-pasv.html

Affected package

python

Latest version: 0.9.8

Affected versions

Fixed versions

Vulnerability changelog

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. See CVE-2021-4189.


MISC:https://access.redhat.com/security/cve/CVE-2021-4189: https://access.redhat.com/security/cve/CVE-2021-4189
MISC:https://bugs.python.org/issue43285: https://bugs.python.org/issue43285
MISC:https://bugzilla.redhat.com/show_bug.cgi?id=2036020: https://bugzilla.redhat.com/show_bug.cgi?id=2036020
MISC:https://github.com/python/cpython/commit/0ab152c6b5d95caa2dc1a30fa96e10258b5f188e: https://github.com/python/cpython/commit/0ab152c6b5d95caa2dc1a30fa96e10258b5f188e
MISC:https://python-security.readthedocs.io/vuln/ftplib-pasv.html: https://python-security.readthedocs.io/vuln/ftplib-pasv.html
MISC:https://security-tracker.debian.org/tracker/CVE-2021-4189: https://security-tracker.debian.org/tracker/CVE-2021-4189

Resources

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Severity Details

CVSS Base Score

MEDIUM 5.3

CVSS v3 Details

MEDIUM 5.3
Attack Vector (AV)
NETWORK
Attack Complexity (AC)
LOW
Privileges Required (PR)
NONE
User Interaction (UI)
NONE
Scope (S)
UNCHANGED
Confidentiality Impact (C)
LOW
Integrity Impact (I)
NONE
Availability Availability (A)
NONE