AUGUST 4, 2026
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Case File

CVE-2021-4189

MEDIUM · CVSS 5.3 EPSS 2.66% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2022-08-24 · Last synced 2026-08-04

CyberRota Analysis

AI analysis pending.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links
github.com ↗

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2021-4189
Severity
MEDIUM
CVSS
5.3
EPSS
2.66%

Original NVD 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.