Bug 2526833

Summary: CVE-2026-63310 python-nltk: NLTK before 3.9.3 Missing Post-Download Integrity Verification [fedora-all]
Product: [Fedora] Fedora Reporter: Samuele Negrini <snegrini>
Component: python-nltkAssignee: José Matos <jamatos>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: jamatos, python-packagers-sig, romain.geissler
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["ee3c8ba1-bb57-4900-bead-a28b1ded3694"]}
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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: 2521337    

Description Samuele Negrini 2026-09-01 15:04:55 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 before 3.9.3 fails to verify file integrity after downloading packages and before extraction in the downloader module. Attackers can perform man-in-the-middle attacks or DNS poisoning to inject malicious package contents that are extracted without validation.