Bug 2498693

Summary:	CVE-2026-15308 python3.9: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Jon Moroney <jmoroney>
Component:	python3.9	Assignee:	Miro Hrončok <mhroncok>
Status:	POST ---	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	high
Version:	45	CC:	cstratak, mhroncok, python-maint, python-packagers-sig, thrnciar, torsava, vstinner
Target Milestone:	---	Keywords:	Reopened, Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["e4e01e88-5029-4403-9e37-e412899c09b1"]}
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-09-07 05:55:28 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:	2498608

Description Jon Moroney 2026-07-09 20:10:20 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.

The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.

Comment 1 Aoife Moloney 2026-08-17 15:16:47 UTC

This bug appears to have been reported against 'rawhide' during the Fedora Linux 45 development cycle.
Changing version to 45.

Comment 2 Miro Hrončok 2026-09-23 12:08:06 UTC

c9s fix is https://gitlab.com/redhat/centos-stream/rpms/python3.9/-/commit/0ad244b12d3adcc81d14e6c9dc974351dc77d2a4 -- we need to forwardport it

Comment 3 Miro Hrončok 2026-09-23 13:02:14 UTC

https://src.fedoraproject.org/rpms/python3.9/pull-request/252