Bug#1131460: nltk: CVE-2026-33236

[Salvatore Bonaccorso]

Source: nltk
Version: 3.9.3-1
Severity: important
Tags: security upstream
X-Debbugs-Cc: carnil at debian.org, Debian Security Team <team at security.debian.org>

Hi,

The following vulnerability was published for nltk.

CVE-2026-33236[0]:
| 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.


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-33236
    https://www.cve.org/CVERecord?id=CVE-2026-33236
[1] https://github.com/nltk/nltk/security/advisories/GHSA-469j-vmhf-r6v7
[2] https://github.com/nltk/nltk/commit/75917efc66ab122bf4b7ea9ffc33e8f8b39c5dce

Please adjust the affected versions in the BTS as needed.

Regards,
Salvatore