nltk

PyPI19 known CVEs affecting this package

Aggregated from OSV, GitHub Security Advisories, NVD, and vendor advisories. Each CVE links to its full detail page with vendor advisories, patches, fixed versions, and remediation guidance.

CVEs affecting nltkpage 1 of 1

CVE-2019-14751HIGHCVSS 7.5EG 7.5✓ Fixed in 3.4.5
2019-08-22
vulnerable: 2.0.1rc2-git ... 3.4.4 (45 versions)
NLTK Downloader before 3.4.5 is vulnerable to a directory traversal, allowing attackers to write arbitrary files via a ../ (dot dot slash) in an NLTK package (ZIP archive) that is mishandled during extraction.
CVE-2021-3828HIGHCVSS 7.5EG 7.5✓ Fixed in 3.6.4
2021-09-27
vulnerable: 0.8 ... 3.6.3 (52 versions)
nltk is vulnerable to Inefficient Regular Expression Complexity
CVE-2021-3842HIGHCVSS 7.5EG 7.5✓ Fixed in 3.6.6
2022-01-04
vulnerable: 0.8 ... 3.6.5 (54 versions)
nltk is vulnerable to Inefficient Regular Expression Complexity
CVE-2021-43854HIGHCVSS 7.5EG 7.5✓ Fixed in 3.6.5
2021-12-23
vulnerable: 0.8 ... 3.6.4 (53 versions)
NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. Versions prior to 3.6.5 are vulnerable to regular expression denial of s…
CVE-2024-39705CRITICALCVSS 9.8EG 9.8✓ Fixed in 3.9
2024-06-27
vulnerable: 0.8 ... 3.9b1 (60 versions)
NLTK through 3.8.1 allows remote code execution if untrusted packages have pickled Python code, and the integrated data package download functionality is used. This affects, for example, averaged_perceptron_tagger and punkt.
CVE-2025-14009HIGHCVSS 8.8EG 8.8✓ Fixed in 3.9.3
2026-02-18
vulnerable: 0.8 ... 3.9b1 (63 versions)
A critical vulnerability exists in the NLTK downloader component of nltk/nltk, affecting all versions. The _unzip_iter function in nltk/downloader.py uses zipfile.extractall() without performing path validation or security checks. This all…
CVE-2026-0846HIGHCVSS 7.5EG 7.5✓ Fixed in 3.9.3
2026-03-09
vulnerable: 0.8 ... 3.9b1 (63 versions)
A vulnerability in the `filestring()` function of the `nltk.util` module in nltk version 3.9.2 allows arbitrary file read due to improper validation of input paths. The function directly opens files specified by user input without sanitiza…
CVE-2026-0847HIGHCVSS 7.5EG 8.6✓ Fixed in 3.9.3
2026-03-04
vulnerable: 0.8 ... 3.9b1 (63 versions)
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail…
CVE-2026-0848CRITICALCVSS 10.0EG 10.0✓ Fixed in 3.9.3
2026-03-05
vulnerable: 0.8 ... 3.9b1 (63 versions)
NLTK versions <=3.9.2 are vulnerable to arbitrary code execution due to improper input validation in the StanfordSegmenter module. The module dynamically loads external Java .jar files without verification or sandboxing. An attacker can su…
CVE-2026-12061HIGHCVSS 7.5EG 7.5✓ Fixed in 3.10.0
2026-07-31
vulnerable: 0.8 ... 3.9b1 (65 versions)
Natural Language Toolkit (NLTK): ReDoS in NLTK ReviewsCorpusReader FEATURES regex ### Summary `ReviewsCorpusReader` extracts feature annotations of the form *label* followed by a bracketed signed digit (e.g. a label then `[+2]`) from each…
CVE-2026-12072HIGHCVSS 7.5EG 7.5✓ Fixed in 3.10.0
2026-07-31
vulnerable: 0.8 ... 3.9b1 (65 versions)
Natural Language Toolkit (NLTK): Path Traversal in NKJPCorpusReader leads to Arbitrary File Read and bypasses the nltk.pathsec sandbox (ENFORCE=True) ### Summary A path-traversal vulnerability in `NKJPCorpusReader` allows an attacker w…
CVE-2026-12074HIGHCVSS 7.5EG 7.5✓ Fixed in 3.10.0
2026-07-31
vulnerable: 0.8 ... 3.9b1 (65 versions)
Natural Language Toolkit (NLTK) has path traversal in FramenetCorpusReader.frame() that allows arbitrary XML file read, bypassing the nltk.pathsec sandbox (ENFORCE=True) ### Summary `FramenetCorpusReader.frame(name)` interpolates a caller…
CVE-2026-12075HIGHCVSS 8.6EG 8.6✓ Fixed in 3.10.0
2026-07-31
vulnerable: 0.8 ... 3.9b1 (65 versions)
Natural Language Toolkit (NLTK): DNS-rebinding SSRF filter bypass in nltk.pathsec.urlopen (nltk.download / nltk.data.load) defeats ENFORCE mode ### Summary `nltk.pathsec` provides an SSRF filter that NLTK documents as a security control, …
CVE-2026-12252HIGHCVSS 7.8EG 7.8✓ Fixed in 3.9.4
2026-07-04
vulnerable: 0.8 ... 3.9b1 (64 versions)
In nltk/nltk versions 3.9.3 and earlier, five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) are vulnerable to untrusted JAR code execution. T…
CVE-2026-33230MEDIUMCVSS 6.1EG 6.1✓ Fixed in 3.9.4
2026-03-20
vulnerable: 0.8 ... 3.9b1 (64 versions)
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, `nltk.app.wordnet_app` contains a reflected…
CVE-2026-33231HIGHCVSS 7.5EG 7.5✓ Fixed in 3.9.4
2026-03-20
vulnerable: 0.8 ... 3.9b1 (64 versions)
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, `nltk.app.wordnet_app` allows unauthenticat…
CVE-2026-33236HIGHCVSS 8.1EG 8.1✓ Fixed in 3.9.4
2026-03-20
vulnerable: 0.8 ... 3.9b1 (64 versions)
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 `…
CVE-2026-54293HIGHCVSS 7.5EG 7.5✓ Fixed in 3.10.0
2026-06-16
vulnerable: 0.8 ... 3.9b1 (65 versions)
NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. Prior to 3.10.0-rc1, nltk.data.load() in NLTK is vulnerable to path trav…
CVE-2026-66393HIGHCVSS 7.5EG 7.5
2026-08-22
vulnerable: 0.8 ... 3.9b1 (64 versions)
NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decode_obj() that allows attackers to cause denial of service by supplying deeply nested JSON structures. Attackers can craft JSON payloads exceed…

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