CVE-2026-33236High· 8.1▾ TwilightNLTK (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…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 44.6 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 10.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
Last analysed / modified upstream
0.5%
0.5% → 0.6%
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.
nltk <= 3.9.3Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
nltk <= 3.9.2Connected by shared product, vendor, weakness, or advisory.
CVE-2026-33231High· 7.5NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing
CVE-2026-79676HighNLTK: Corpus readers follow symlinks outside trusted roots despite pathsec enforcement
CVE-2026-63312High· 7.5NLTK before 3.10.0 contains an arbitrary local file read vulnerability in StreamBackedCorpusView that bypasses pathsec.ENFORCE by calling builtins.open() directly instead of pathsec.open()
CVE-2026-62385Medium· 5.9NLTK versions before 3.10.0 contain a path traversal vulnerability in FramenetCorpusReader and NKJPCorpusReader that allows attackers to parse XML files outside the corpus root by supplying unsafe selectors or poisoned index state
CVE-2026-62384High· 7.5NLTK versions before 3.10.2 contain a symlink-based sandbox bypass in FramenetCorpusReader that allows attackers to read arbitrary XML files outside the corpus root
CVE-2026-62383Medium· 5.5nltk versions before 3.10.2 contain a symlink-based arbitrary file read vulnerability in IPIPANCorpusReader methods that bypass nltk.pathsec validation entirely