nltk 関連製品全体の CVE とセキュリティ脆弱性情報を集約し、CVSS、EPSS、公開日、脆弱性情報データを掲載しています。
公開された問題は パス処理の欠陥、vendor risk cross-site scripting, and vendor risk input validation に関連することが多く、vendor surface software deployment and vendor surface production workloads の文脈で ファイル上書き and vendor impact unexpected behavior などの暴露リスクを伴う場合があります。
掲載データは公開脆弱性情報とセキュリティ公告に基づき、過去の暴露面と修補優先度の評価に利用できます。
| CVE | 概要 | ソース | CVSS 最大値 | EPSS（%） | 公開 | 更新 |
|---|---|---|---|---|---|---|
| CVE-2026-54293 | 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 traversal via URL-encoded path separators and traversal segments when using the nltk: URL scheme. The unsafe-path regex check is performed before url2pathname() decodes the %xx sequences (a classic decode-after-check / TOCTOU-style flaw), allowing an attacker to by | [email protected] | 7.5 | 0.44% | 2026-06-22 | 2026-06-26 |
| CVE-2026-33236 | 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 c | [email protected] | 8.1 | 0.40% | 2026-03-20 | 2026-06-17 |
| CVE-2026-33231 | 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 unauthenticated remote shutdown of the local WordNet Browser HTTP server when it is started in its default mode. A simple `GET /SHUTDOWN%20THE%20SERVER` request causes the process to terminate immediately via `os._exit(0)`, resulting in a denial of service. Commit bbaae83db | [email protected] | 7.5 | 0.54% | 2026-03-20 | 2026-06-17 |
| CVE-2026-33230 | 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 cross-site scripting issue in the `lookup_...` route. A crafted `lookup_<payload>` URL can inject arbitrary HTML/JavaScript into the response page because attacker-controlled `word` data is reflected into HTML without escaping. This impacts users running the l | [email protected] | 6.1 | 0.33% | 2026-03-20 | 2026-06-17 |
| CVE-2026-0846 | 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 sanitization, enabling attackers to access sensitive system files by providing absolute paths or traversal paths. This vulnerability can be exploited locally or remotely, particularly in scenarios where the function is used in web APIs or other interfaces that accept u | [email protected] | 7.5 | 0.36% | 2026-03-09 | 2026-06-17 |
| CVE-2026-0848 | 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 supply or replace the JAR file, enabling the execution of arbitrary Java bytecode at import time. This vulnerability can be exploited through methods such as model poisoning, MITM attacks, or dependency poisoning, leading to remote code execution. The issue arise | [email protected] | 10.0 | 0.78% | 2026-03-05 | 2026-06-17 |
| CVE-2026-0847 | 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 to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs | [email protected] | 7.5 | 0.75% | 2026-03-04 | 2026-06-17 |
| CVE-2025-14009 | 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 allows attackers to craft malicious zip packages that, when downloaded and extracted by NLTK, can execute arbitrary code. The vulnerability arises because NLTK assumes all downloaded packages are trusted and extracts them without validation. If a malicious package | [email protected] | 10.0 | 0.71% | 2026-02-18 | 2026-06-17 |
| CVE-2021-3842 | nltk is vulnerable to Inefficient Regular Expression Complexity | [email protected] | 7.5 | 1.50% | 2022-01-04 | 2026-06-17 |
| CVE-2021-43854 | 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 service (ReDoS) attacks. The vulnerability is present in PunktSentenceTokenizer, sent_tokenize and word_tokenize. Any users of this class, or these two functions, are vulnerable to the ReDoS attack. In short, a specifically crafted long input to any of these vul | [email protected] | 7.5 | 2.67% | 2021-12-23 | 2026-06-17 |
| CVE-2021-3828 | nltk is vulnerable to Inefficient Regular Expression Complexity | [email protected] | 7.5 | 1.58% | 2021-09-27 | 2026-06-17 |
| CVE-2019-14751 | 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. | [email protected] | 7.5 | 5.83% | 2019-08-22 | 2026-06-16 |