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.
Metrics
CVSS 3.1 5.3/10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| n/a | python | Fixed in python 3.6.14, python 3.7.11, python 3.8.9, python 3.9.3, python 3.10.0 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP | >= V3.1.0, < V3.1.5 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP | >= V3.1.0, < V3.1.5 |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP | >= V3.1.0, < V3.1.5 |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP | >= V3.1.0, < V3.1.5 |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP | >= V3.1.0, < V3.1.5 |
References
- https://access.redhat.com/security/cve/CVE-2021-4189Third Party Advisory
- https://bugs.python.org/issue43285Patch, Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2036020Issue Tracking, Patch, Third Party Advisory
- https://github.com/python/cpython/commit/0ab152c6b5d95caa2dc1a30fa96e10258b5f188ePatch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
- https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html
- https://python-security.readthedocs.io/vuln/ftplib-pasv.htmlPatch, Third Party Advisory
- https://security-tracker.debian.org/tracker/CVE-2021-4189Third Party Advisory
- https://security.netapp.com/advisory/ntap-20221104-0004/Third Party Advisory
- https://access.redhat.com/security/cve/CVE-2021-4189Third Party Advisory
- https://bugs.python.org/issue43285Patch, Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2036020Issue Tracking, Patch, Third Party Advisory
- https://github.com/python/cpython/commit/0ab152c6b5d95caa2dc1a30fa96e10258b5f188ePatch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
- https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html
- https://lists.debian.org/debian-lts-announce/2024/12/msg00000.html
- https://python-security.readthedocs.io/vuln/ftplib-pasv.htmlPatch, Third Party Advisory
- https://security-tracker.debian.org/tracker/CVE-2021-4189Third Party Advisory
- https://security.netapp.com/advisory/ntap-20221104-0004/Third Party Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html
Timeline
- Published
- Aug 24, 2022
- Last modified
- Nov 10, 2026
- NVD status
- Modified