{"id":"CVE-2021-3842","aliases":["GHSA-rqjh-jp2r-59cj","PYSEC-2022-5"],"url":"https://o3.security/vulnerability/CVE-2021-3842","summary":"NLTK Vulnerable to REDoS","details":"nltk is vulnerable to Inefficient Regular Expression Complexity","published":"2022-01-04T15:15:07.833Z","modified":"2026-07-08T05:59:50.266100163Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"PyPI","name":"nltk","fixedVersion":"3.6.6"}],"fix":{"url":"https://github.com/nltk/nltk/commit/2a50a3edc9d35f57ae42a921c621edc160877f4d","label":"nltk/nltk@2a50a3e"},"references":[{"type":"FIX","url":"https://github.com/nltk/nltk/commit/2a50a3edc9d35f57ae42a921c621edc160877f4d"},{"type":"FIX","url":"https://huntr.dev/bounties/761a761e-2be2-430a-8d92-6f74ffe9866a"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-08T05:59:50.266100163Z"}}