[3.10] gh-87451: Apply CVE-2021-4189 PASV fix to ftplib.ftpcp() (GH-149648) - #149797
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pablogsal merged 1 commit intoJun 27, 2026
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[3.10] gh-87451: Apply CVE-2021-4189 PASV fix to ftplib.ftpcp() (GH-149648)#149797pablogsal merged 1 commit into
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…nGH-149648) 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 at Aurascape AI for the report. (GHSA-w8c5-q2xf-gf7c) (cherry picked from commit eac4fe3) Co-authored-by: Gregory P. Smith <68491+gpshead@users.noreply.github.com>
This was referenced May 13, 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 at Aurascape AI for the report. (GHSA-w8c5-q2xf-gf7c)
(cherry picked from commit eac4fe3)
Co-authored-by: Gregory P. Smith 68491+gpshead@users.noreply.github.com