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

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@miss-islington

@miss-islington miss-islington commented May 13, 2026 •
edited by bedevere-app Bot
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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 [email protected]

  • Issue: ftplib should not use the host from the PASV response #87451

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All reactions
@gpshead @miss-islington
pythongh-87451: Apply CVE-2021-4189 PASV fix to ftplib.ftpcp() (pytho…
6ff8d1b
…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 <[email protected]>
This was referenced May 13, 2026
ftplib should not use the host from the PASV response #87451
Closed
gh-87451: Apply CVE-2021-4189 PASV fix to ftplib.ftpcp() #149648
Merged
@bedevere-app bedevere-app Bot added type-security A security issue awaiting review labels May 13, 2026
@gpshead
gpshead enabled auto-merge (squash) May 13, 2026 17:53
@gpshead
gpshead merged commit 7d95a1d into python:3.14 May 13, 2026
52 checks passed

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@bedevere-app bedevere-app Bot removed the awaiting review label May 13, 2026
@miss-islington
miss-islington deleted the backport-eac4fe3-3.14 branch May 13, 2026 17:59
LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request May 17, 2026
@LearningCircuit
chore(security): suppress CVE-2026-8328 (ftplib.ftpcp SSRF) until 3.14.6
e31572d
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 LearningCircuit mentioned this pull request May 17, 2026
chore(security): suppress CVE-2026-8328 (ftplib.ftpcp SSRF) until 3.14.6 LearningCircuit/local-deep-research#4072
Merged
2 tasks
LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request May 17, 2026
@LearningCircuit
chore(security): suppress CVE-2026-8328 (ftplib.ftpcp SSRF) until 3.1…
0fe3c8c
…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+.
LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request Jun 22, 2026
@LearningCircuit
chore(security): suppress CVE-2026-8328 (ftplib.ftpcp SSRF) until 3.1…
28dd46b
…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+.
LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request Jun 22, 2026
@LearningCircuit
chore(security): suppress CVE-2026-8328 (ftplib.ftpcp SSRF) until 3.1…
2e4d596
…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+.
LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request Jun 22, 2026
@LearningCircuit
chore(security): suppress CVE-2026-8328 (ftplib.ftpcp SSRF) until 3.1…
bfb3ac9
…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+.
LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request Jun 22, 2026
@LearningCircuit
chore(security): suppress CVE-2026-8328 (ftplib.ftpcp SSRF) until 3.1…
cf95658
…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+.
LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request Jun 22, 2026
@LearningCircuit
chore(security): suppress CVE-2026-8328 (ftplib.ftpcp SSRF) until 3.1…
1e155c9
…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+.
LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request Jun 22, 2026
@LearningCircuit
chore(security): suppress CVE-2026-8328 (ftplib.ftpcp SSRF) until 3.1…
22fc4c5
…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+.
LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request Jun 22, 2026
@LearningCircuit
chore(security): suppress CVE-2026-8328 (ftplib.ftpcp SSRF) until 3.1…
12bc727
…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+.
LearningCircuit added a commit to LearningCircuit/local-deep-research that referenced this pull request Jun 22, 2026
@LearningCircuit
chore(security): suppress CVE-2026-8328 (ftplib.ftpcp SSRF) until 3.1…
6f1e818
…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+.
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@miss-islington @gpshead
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