[3.14] gh-87451: Apply CVE-2021-4189 PASV fix to ftplib.ftpcp() (GH-149648) by miss-islington · Pull Request #149793 · python/cpython

bedevere-app

…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

LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request

May 17, 2026

Grype alerts on CVE-2026-8328 against python:3.14.5-slim. The
vulnerability is an SSRF in the undocumented ftplib.ftpcp() helper —
the same PASV-trust class as CVE-2021-4189, whose original 2021 fix
only patched ftplib.FTP and left ftpcp() unprotected.

Upstream merged the fix to the CPython 3.14 branch on 2026-05-13
(python/cpython#149793), three days after Python 3.14.5 was tagged.
No 3.14.6 release exists yet, so a base-image bump isn't an option.

Not exploitable here: `grep -rn "ftplib\|ftpcp" src/` returns zero
hits, and no transitive dependency imports ftplib either, so
ftpcp() is unreachable from this image.

Added to .grype.yaml in the existing python3.14 block alongside the
other CPython CVEs awaiting the next 3.14.x point release. The
suppression auto-cleans when the next Python bump picks up 3.14.6+.

LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request

May 17, 2026

…4.6 (#4072)

Grype alerts on CVE-2026-8328 against python:3.14.5-slim. The
vulnerability is an SSRF in the undocumented ftplib.ftpcp() helper —
the same PASV-trust class as CVE-2021-4189, whose original 2021 fix
only patched ftplib.FTP and left ftpcp() unprotected.

Upstream merged the fix to the CPython 3.14 branch on 2026-05-13
(python/cpython#149793), three days after Python 3.14.5 was tagged.
No 3.14.6 release exists yet, so a base-image bump isn't an option.

Not exploitable here: `grep -rn "ftplib\|ftpcp" src/` returns zero
hits, and no transitive dependency imports ftplib either, so
ftpcp() is unreachable from this image.

Added to .grype.yaml in the existing python3.14 block alongside the
other CPython CVEs awaiting the next 3.14.x point release. The
suppression auto-cleans when the next Python bump picks up 3.14.6+.