CVE intelligence and bounded remediation

CVE-2021-4189 — A flaw was found in Python, specifically in the FTP (File Transfer Protocol) client library in PASV (passive) mode

Medium CVSS 5.3

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.

Severity
Medium
CVSS
5.3 (3.1)
Published
2022-08-24
CISA KEV
Not currently listed
Ecosystem
python/pypi
Weaknesses
CWE-252

Affected products

  • python / python
  • python / python / 3.10.0
  • debian / debian_linux / 10.0
  • debian / debian_linux / 11.0
  • redhat / software_collections
  • redhat / enterprise_linux / 8.0

Showing 6 representative product identities from 10 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

General vulnerability remediation

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Confirm the affected component, deployment paths, reachable interfaces, and enabled features from inventories and configuration, without probing production destructively.
  • Compare the advisory's affected conditions with the repository lockfiles, build manifests, artifacts, and runtime inventory.
  • Identify data sensitivity, trust boundaries, and privilege level for every confirmed affected deployment.

Remediate safely

  • Apply a vendor-supported fix or remove the affected component or feature; record the selected change and its source in the repository.
  • Update direct and transitive dependency locks, generated artifacts, deployment manifests, and asset inventories together.
  • Add a regression test for the documented unsafe condition using inert inputs and preserve rollback instructions.

Authoritative sources

Complete CVE record and remediation plan

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