{"action":"Upgrade nltk to 3.9.3 or later.","affected":[{"fixed":"3.9.3","introduced":"0"}],"component":"nltk","cve_ids":["CVE-2026-12259","CVE-2026-63310"],"ecosystem":"PyPI","exploited":false,"fixed_versions":["3.9.3"],"ghsa_id":"GHSA-5wp5-5229-5g6q","id":"tcs_01M5JHHMTEYP2QHK9ANRKM5QP4","modified_at":"2026-10-16T10:56:05.808390648Z","published_at":"2026-08-22T15:16:19.100Z","references":["https://osv.dev/vulnerability/PYSEC-2026-3729","https://www.vulncheck.com/advisories/nltk-before-missing-post-download-integrity-verification","https://github.com/nltk/nltk/security/advisories/GHSA-5wp5-5229-5g6q","https://github.com/advisories/GHSA-5wp5-5229-5g6q"],"severity":{"label":"medium","score":6.5},"sources":[{"source":"osv","source_id":"PYSEC-2026-3729","url":"https://osv.dev/vulnerability/PYSEC-2026-3729"}],"summary":"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 m"}