Bug 2428948

Summary: CVE-2025-13836 python3.9: Excessive read buffering DoS in http.client [fedora-43]
Product: [Fedora] Fedora Reporter: Guilherme de Almeida Suckevicz <gsuckevi>
Component: python3.9Assignee: Python Maintainers <python-maint>
Status: CLOSED NOTABUG QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: 43CC: cstratak, mhroncok, python-maint, python-packagers-sig, thrnciar, torsava, vstinner
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["7756d08c-def2-42bc-ae62-aa8be84272eb"]}
Fixed In Version: Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-01-14 14:00:33 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: 2418078    

Description Guilherme de Almeida Suckevicz 2026-01-13 12:42:34 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 following link provides references to all essential vulnerability management information. If something is wrong or missing, please contact a member of PSIRT.
https://spaces.redhat.com/display/PRODSEC/Vulnerability+Management+-+Essential+Documents+for+Engineering+Teams
Comment 1 Lumír Balhar 2026-01-14 14:00:33 UTC 
We've verified that Python 3.6 and 3.9 are not vulnerable to this vulnerability. The problematic code was introduced multiple times with optimizations, and we verified that it's not in these releases and confirmed our opinion with a reproducer for this vulnerability.