gh-87451: Apply CVE-2021-4189 PASV fix to ftplib.ftpcp()#149648
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gpshead wants to merge 2 commits intopython:mainfrom
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gh-87451: Apply CVE-2021-4189 PASV fix to ftplib.ftpcp()#149648gpshead wants to merge 2 commits intopython:mainfrom
gpshead wants to merge 2 commits intopython:mainfrom
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ftpcp() called parse227() directly and passed the source server's self-reported PASV IPv4 address to the target server's PORT command, bypassing the CVE-2021-4189 fix that was applied only to FTP.makepasv(). A malicious source FTP server could use this to redirect the target server's data connection to an arbitrary host:port (SSRF). ftpcp() now uses the source server's actual peer address, honoring the existing trust_server_pasv_ipv4_address opt-out, the same as makepasv(). Thanks to Qi Ding (AKA ikow) for the report.
gpshead
added
needs backport to 3.10
Documentation build overview
102 files changed ·
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picnixz
reviewed
May 10, 2026
| source server's actual peer address instead, the same as FTP.makepasv(). | ||
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| class _FakeSock: |
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Do we need those fake classes or can't we just use Mock() objects instead? Just asking.
picnixz
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May 10, 2026
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ftpcp() called parse227() directly and passed the source server's self-reported PASV IPv4 address to the target server's PORT command, bypassing the CVE-2021-4189 fix that was applied only to FTP.makepasv(). A malicious source FTP server could use this to redirect the target server's data connection to an arbitrary host:port (SSRF).
ftpcp() now uses the source server's actual peer address, honoring the existing trust_server_pasv_ipv4_address opt-out, the same as makepasv().
Thanks to Qi Ding (AKA ikow) for the report. (GHSA-w8c5-q2xf-gf7c)