USN-8302-1: NLTK vulnerabilities

Publication date

25 May 2026

Overview

Several security issues were fixed in NLTK.


Packages

  • nltk - Natural Language Toolkit

Details

It was discovered that NLTK incorrectly validated file paths when
opening files using the nltk.util module. An attacker could possibly
use this issue to obtain sensitive information. (CVE-2026-0846)

It was discovered that NLTK incorrectly validated file paths in
multiple CorpusReader classes. An attacker could possibly use
this issue to obtain sensitive information. (CVE-2026-0847)

It was discovered that NLTK did not properly validate external
Java archive files loaded by StanfordSegmenter. An attacker
could possibly use this issue to execute arbitrary code. This
issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu
22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS.
(CVE-2026-0848)

It was discovered that NLTK's WordNet browser application
incorrectly handled user-supplied input. An attacker...

It was discovered that NLTK incorrectly validated file paths when
opening files using the nltk.util module. An attacker could possibly
use this issue to obtain sensitive information. (CVE-2026-0846)

It was discovered that NLTK incorrectly validated file paths in
multiple CorpusReader classes. An attacker could possibly use
this issue to obtain sensitive information. (CVE-2026-0847)

It was discovered that NLTK did not properly validate external
Java archive files loaded by StanfordSegmenter. An attacker
could possibly use this issue to execute arbitrary code. This
issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu
22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS.
(CVE-2026-0848)

It was discovered that NLTK's WordNet browser application
incorrectly handled user-supplied input. An attacker could
possibly use this issue to perform a cross-site scripting
attack. (CVE-2026-33230)

It was discovered that NLTK's WordNet browser application did
not restrict access to the shutdown endpoint. A remote attacker
could possibly use this issue to cause a denial of service.
(CVE-2026-33231)

It was discovered that NLTK's downloader did not validate path
attributes in remote XML index files. An attacker could possibly
use this issue to create or overwrite arbitrary files.
(CVE-2026-33236)


Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
26.04 LTS resolute python3-nltk –  3.9.2-1ubuntu0.1~esm2  
24.04 LTS noble python3-nltk –  3.8.1-1ubuntu0.1~esm2  
22.04 LTS jammy python3-nltk –  3.7-1ubuntu0.1~esm2  
20.04 LTS focal python3-nltk –  3.4.5-2ubuntu0.1~esm4  
18.04 LTS bionic python-nltk –  3.2.5-1ubuntu0.1+esm4  
python3-nltk –  3.2.5-1ubuntu0.1+esm4  
16.04 LTS xenial python-nltk –  3.1-1ubuntu0.1+esm4
python3-nltk –  3.1-1ubuntu0.1+esm4
14.04 LTS trusty python-nltk –  2.0~b9-0ubuntu4.1~esm6  

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