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(). This patch is related to CVE-2021-4189.
CVSS Details
- CVSS 4.0 Base Score: 5.9 (MEDIUM)
- CVSS 4.0 Vector: (CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade python3 | Aug 17, 2026 | May 13, 2026 |
| Debian | — | Upgrade python3.13 | Jul 23, 2026 | Jul 23, 2026 |
| Ubuntu | — | Upgrade libpython3.14Upgrade python3.12Upgrade libpython3.12t64Upgrade python3.10Upgrade python3.14Upgrade libpython3.10 | Jul 6, 2026 | May 13, 2026 |
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