There is a MEDIUM severity vulnerability affecting CPython.

The ftpcp() function in Lib/ftplib.py was not updated when CVE-2021-4189 was fixed. While makepasv() was patched to replace server-supplied PASV host addresses with the actual peer address (getpeername()[0]), ftpcp() still calls parse227() directly and passes the raw attacker-controllable IP address and port to target.sendport().

Please see the linked CVE ID for the latest information on affected versions:

• https://www.cve.org/CVERecord?id=CVE-2026-8328
• https://github.com/python/cpython/pull/149648