gh-87451: Apply CVE-2021-4189 PASV fix to ftplib.ftpcp()#149648
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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
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needs backport to 3.10
Documentation build overview
102 files changed ·
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picnixz
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picnixz
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May 10, 2026
…pcp test Replace the _Fake* helper classes in TestFtpcpSecurity with mock.Mock objects spec'd against ftplib.FTP. The spec gives a real-API check that ftpcp() only touches attributes that exist on FTP, and a keyword-only _make_pair() helper keeps the call sites self-documenting.
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Thanks @gpshead for the PR 🌮🎉.. I'm working now to backport this PR to: 3.10, 3.11, 3.12, 3.13, 3.14, 3.15. |
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GH-149792 is a backport of this pull request to the 3.15 branch. |
bedevere-app
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GH-149793 is a backport of this pull request to the 3.14 branch. |
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GH-149794 is a backport of this pull request to the 3.13 branch. |
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GH-149795 is a backport of this pull request to the 3.12 branch. |
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GH-149796 is a backport of this pull request to the 3.11 branch. |
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GH-149797 is a backport of this pull request to the 3.10 branch. |
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…49648) (#149794) gh-87451: Apply CVE-2021-4189 PASV fix to ftplib.ftpcp() (GH-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>
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May 13, 2026
…49648) (#149793) gh-87451: Apply CVE-2021-4189 PASV fix to ftplib.ftpcp() (GH-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>
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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 Deng at Aurascape AI for the report. (GHSA-w8c5-q2xf-gf7c)