{"id":"PYSEC-2026-2237","details":"NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. In versions 3.9.3 and prior, the NLTK downloader does not validate the `subdir` and `id` attributes when processing remote XML index files. Attackers can control a remote XML index server to provide malicious values containing path traversal sequences (such as `../`), which can lead to arbitrary directory creation, arbitrary file creation, and arbitrary file overwrite. Commit 89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a patches the issue.","aliases":["CVE-2026-33236","GHSA-469j-vmhf-r6v7"],"modified":"2026-07-13T07:30:58.022553933Z","published":"2026-03-20T23:16:47.007Z","references":[{"type":"WEB","url":"https://access.redhat.com/security/cve/CVE-2026-33236"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33236.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:10184"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:19712"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:37275"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2449824"},{"type":"FIX","url":"https://github.com/nltk/nltk/commit/89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a"},{"type":"EVIDENCE","url":"https://github.com/nltk/nltk/security/advisories/GHSA-469j-vmhf-r6v7"}],"affected":[{"package":{"name":"nltk","ecosystem":"PyPI","purl":"pkg:pypi/nltk"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.9.4"}]}],"versions":["0.8","0.9","0.9.3","0.9.4","0.9.5","0.9.6","0.9.7","0.9.8","0.9.9","2.0.1","2.0.1rc1","2.0.1rc2-git","2.0.1rc3","2.0.1rc4","2.0.2","2.0.3","2.0.4","2.0.5","2.0b4","2.0b5","2.0b6","2.0b7","2.0b8","2.0b9","3.0.0","3.0.0b1","3.0.0b2","3.0.1","3.0.2","3.0.3","3.0.4","3.0.5","3.1","3.2","3.2.1","3.2.2","3.2.3","3.2.4","3.2.5","3.3","3.4","3.4.1","3.4.2","3.4.3","3.4.4","3.4.5","3.5","3.5b1","3.6","3.6.1","3.6.2","3.6.3","3.6.4","3.6.5","3.6.6","3.6.7","3.7","3.8","3.8.1","3.9","3.9.1","3.9.2","3.9.3","3.9b1"],"ecosystem_specific":{},"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/nltk/PYSEC-2026-2237.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H"}]}