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.
History

Mon, 23 Mar 2026 19:30:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*

Mon, 23 Mar 2026 17:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 23 Mar 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Mon, 23 Mar 2026 10:00:00 +0000

Type Values Removed Values Added
First Time appeared Nltk
Nltk nltk
Vendors & Products Nltk
Nltk nltk

Fri, 20 Mar 2026 23:00:00 +0000

Type Values Removed Values Added
Description 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.
Title NLTK has a Downloader Path Traversal Vulnerability (AFO) - Arbitrary File Overwrite
Weaknesses CWE-22
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-03-20T22:47:10.308Z

Updated: 2026-03-23T16:46:42.554Z

Reserved: 2026-03-18T02:42:27.508Z

Link: CVE-2026-33236

cve-icon Vulnrichment

Updated: 2026-03-23T16:46:38.279Z

cve-icon NVD

Status : Analyzed

Published: 2026-03-20T23:16:47.007

Modified: 2026-03-23T19:15:37.720

Link: CVE-2026-33236

cve-icon Redhat

Severity : Important

Publid Date: 2026-03-20T22:47:10Z

Links: CVE-2026-33236 - Bugzilla