{"action":"Upgrade nltk to 3.6.6 or later.","affected":[{"fixed":"3.6.6","introduced":"0"}],"component":"nltk","cve_ids":["CVE-2021-43854"],"ecosystem":"PyPI","epss":0.0279,"exploited":false,"fixed_versions":["3.6.6"],"ghsa_id":"GHSA-f8m6-h2c7-8h9x","id":"tcs_01M5KFEW239AE6XTVGNVH0NSNF","modified_at":"2026-07-08T06:28:12.494495711Z","published_at":"2022-01-06T17:38:45Z","references":["https://osv.dev/vulnerability/GHSA-f8m6-h2c7-8h9x","https://github.com/nltk/nltk/security/advisories/GHSA-f8m6-h2c7-8h9x","https://nvd.nist.gov/vuln/detail/CVE-2021-43854","https://github.com/nltk/nltk/issues/2866","https://github.com/nltk/nltk/pull/2869","https://github.com/nltk/nltk/commit/1405aad979c6b8080dbbc8e0858f89b2e3690341","https://github.com/nltk/nltk","https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2021-859.yaml"],"severity":{"label":"high","score":7.5},"sources":[{"source":"osv","source_id":"GHSA-f8m6-h2c7-8h9x","url":"https://osv.dev/vulnerability/GHSA-f8m6-h2c7-8h9x"}],"summary":"Inefficient Regular Expression Complexity in nltk (word_tokenize, sent_tokenize)"}