Medium severity · published Aug 24, 2022
CVE-2021-4189
A flaw was found in Python, specifically in the FTP (File Transfer Protocol) client library in PASV (passive) mode
5.3
CVSS
3.4%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)3.4% · higher than 89% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PY
python ·
Fixed in python 3.6.14, python 3.7.11, python 3.8.9, python 3.9.3, python 3.10.0 · source: vendor, NVD
DL
Debian Linux · Debian
10.0; 11.0 · source: NVD
EL
Enterprise Linux · Redhat
8.0 · source: NVD
OS
Ontap Select Deploy Administration Utility · Netapp
All versions, or not specified · source: NVD
SC
Software Collections · Redhat
All versions, or not specified · source: NVD
SS
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP · Siemens
V3.1.0 before V3.1.5; V3.1.0 before V3.1.5 · source: CISA
SS
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP · Siemens
V3.1.0 before V3.1.5; V3.1.0 before V3.1.5 · source: CISA
SS
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP · Siemens
V3.1.0 before V3.1.5 · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-4189
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-4189
Third Party Advisory
https://access.redhat.com/security/cve/CVE-2021-4189
Patch
https://bugs.python.org/issue43285
Issue Tracking
https://bugzilla.redhat.com/show_bug.cgi?id=2036020
Patch
https://github.com/python/cpython/commit/0ab152c6b5d95caa2dc1a30fa96e10258b5f188e
lists.debian.org
https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
lists.debian.org
https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html
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