NLTK vulnerabilities

Summary

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) Affected Ubuntu releases: 26.04, 24.04, 22.04, 20.04, 18.04, 16.04, 14.04. CVEs: CVE-2026-33230, CVE-2026-0846, CVE-2026-33231, CVE-2026-0848, CVE-2026-0847, CVE-2026-33236.