Bug 2540194

Summary: CVE-2026-91990 python-pep517: Tornado: Denial of Service via memory amplification in multipart parsing [epel-all]
Product: [Fedora] Fedora EPEL Reporter: Ganesh <gnaik>
Component: python-pep517Assignee: Orphan Owner <extras-orphan>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: epel10CC: encukou, extras-orphan, python-packagers-sig
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["acde6b02-d0b7-46a6-82c2-8dde917ba695"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2533953    

Description Ganesh 2026-09-24 15:22:44 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.

Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form_data that splits multipart data before validating the max_parts limit. Attackers can send crafted multipart requests with many parts to create large transient lists, exhausting server memory and causing denial of service.