Bug 2545940

Summary:	CVE-2026-19445 python3.13: Use-after-free of a server-side SSLContext when sni_callback switches contexts [epel-all]
Product:	[Fedora] Fedora EPEL	Reporter:	Srikanth Balasubramanian <sbalasub>
Component:	python3.13	Assignee:	Python Maintainers <python-maint>
Status:	CLOSED ERRATA	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	epel10	CC:	ksurma, mhroncok, python-maint, python-packagers-sig
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["5337ec1f-6905-4942-a83c-22a9673b156c"]}
Fixed In Version:	python3.13-3.13.16-1.el10_2 python3.13-3.13.16-1.el10_4 python3.13-3.13.16-1.el10_3 python3.13-3.13.16-1.el9	Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-10-09 01:14:42 UTC	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 15:17:01 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 2026-10-05 15:45:09 UTC

FEDORA-EPEL-2026-0781e8eb3f (python3.13-3.13.16-1.el10_3) has been submitted as an update to Fedora EPEL 10.3.
https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-0781e8eb3f

Comment 2 Fedora Update System 2026-10-05 15:45:15 UTC

FEDORA-EPEL-2026-d64ba97176 (python3.13-3.13.16-1.el9) has been submitted as an update to Fedora EPEL 9.
https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-d64ba97176

Comment 3 Fedora Update System 2026-10-05 15:45:19 UTC

FEDORA-EPEL-2026-5dfbf08d30 (python3.13-3.13.16-1.el10_2) has been submitted as an update to Fedora EPEL 10.2.
https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-5dfbf08d30

Comment 4 Fedora Update System 2026-10-09 01:14:42 UTC

FEDORA-EPEL-2026-5dfbf08d30 (python3.13-3.13.16-1.el10_2) has been pushed to the Fedora EPEL 10.2 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 5 Fedora Update System 2026-10-10 00:29:36 UTC

FEDORA-EPEL-2026-0498f387fb (python3.13-3.13.16-1.el10_4) has been pushed to the Fedora EPEL 10.4 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 6 Fedora Update System 2026-10-12 00:23:50 UTC

FEDORA-EPEL-2026-0781e8eb3f (python3.13-3.13.16-1.el10_3) has been pushed to the Fedora EPEL 10.3 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 7 Fedora Update System 2026-10-12 00:35:18 UTC

FEDORA-EPEL-2026-d64ba97176 (python3.13-3.13.16-1.el9) has been pushed to the Fedora EPEL 9 stable repository.
If problem still persists, please make note of it in this bug report.