Bug 2527837

Summary: CVE-2026-81723 python-nltk: NLTK: Denial of Service via malformed XML corpus files [epel-all]
Product: [Fedora] Fedora EPEL Reporter: Ganesh <gnaik>
Component: python-nltkAssignee: Romain Geissler <romain.geissler>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: epel10CC: jamatos, python-packagers-sig, romain.geissler
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["7b5f63fb-db2d-4f34-8331-fa156be234d2"]}
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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: 2525090    

Description Ganesh 2026-09-03 07:31:34 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.

NLTK versions before 3.10.3 contain a quadratic CPU exhaustion vulnerability in XMLCorpusView._read_xml_fragment() that rescans accumulated XML fragments on every 1 KiB block read. Attackers can provide malformed XML corpus files to cause severe CPU consumption and denial of service through affected readers like BNCCorpusReader.