Bug 2545941

Summary:	CVE-2026-19445 mingw-python3: Use-after-free of a server-side SSLContext when sni_callback switches contexts [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Srikanth Balasubramanian <sbalasub>
Component:	mingw-python3	Assignee:	Sandro Mani <manisandro>
Status:	ON_QA ---	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	high
Version:	rawhide	CC:	manisandro
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["5337ec1f-6905-4942-a83c-22a9673b156c"]}
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2544138

Description Srikanth Balasubramanian 2026-10-05 15:17:54 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

A remote, unauthenticated TLS client can make a server crash or call
through a freed pointer if its sni_callback assigns a different context to
SSLSocket.context (the documented way to select a certificate per server
name) and nothing else keeps the original ssl.SSLContext alive. Typical
cases are servers that create an SSLContext per connection or replace it
while connections are open; servers that wrap their listening socket with
it are not affected.


Mitigation: keep a reference to every SSLContext that sets sni_callback for
the lifetime of the server. TLS clients are not affected.

Comment 1 Fedora Update System 2026-10-18 13:02:54 UTC

FEDORA-2026-7740bc798f (mingw-python3-3.11.17-1.fc45) has been submitted as an update to Fedora 45.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-7740bc798f

Comment 2 Fedora Update System 2026-10-18 13:03:23 UTC

FEDORA-2026-aa5c18e9be (mingw-python3-3.11.17-1.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-aa5c18e9be

Comment 3 Fedora Update System 2026-10-19 01:53:29 UTC

FEDORA-2026-7740bc798f has been pushed to the Fedora 45 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-7740bc798f`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-7740bc798f

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 4 Fedora Update System 2026-10-19 02:13:35 UTC

FEDORA-2026-aa5c18e9be has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-aa5c18e9be`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-aa5c18e9be

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.