# CVE-2026-33231: nltk: NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting researc...

CVE-2026-33231 is fixed in 3 products on 1 platform, first by python-nltk 3.2.5-1ubuntu0.1+esm4, released March 20, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-33231
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0126
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 20, 2026

## Description

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 bbaae83db86a0f49e00f5b0db44a7254c268de9b patches the issue.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | nltk Debian 14 | 3.10.0-1 | [DEBIAN-CVE-2026-33231](https://patchblox.com/security/data/fix/linux/debian-cve-2026-33231.md) | Mar 20, 2026 |
| Linux | python-nltk Ubuntu 18.04.6 LTS (bionic) | 3.2.5-1ubuntu0.1+esm4 | [python-nltk 3.2.5-1ubuntu0.1+esm4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python-nltk-3.2.5-1ubuntu0.1-esm4.md) | Mar 20, 2026 |
| Linux | python3-nltk Ubuntu 18.04.6 LTS (bionic) | 3.2.5-1ubuntu0.1+esm4 | [python3-nltk 3.2.5-1ubuntu0.1+esm4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python3-nltk-3.2.5-1ubuntu0.1-esm4.md) | Mar 20, 2026 |
| Linux | python3-nltk Ubuntu 20.04 LTS (focal) | 3.4.5-2ubuntu0.1~esm4 | [python3-nltk 3.4.5-2ubuntu0.1~esm4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-python3-nltk-3.4.5-2ubuntu0.1-esm4.md) | Mar 20, 2026 |
| Linux | python3-nltk Ubuntu 22.04.1 LTS (jammy) | 3.7-1ubuntu0.1~esm2 | [python3-nltk 3.7-1ubuntu0.1~esm2](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-nltk-3.7-1ubuntu0.1-esm2.md) | Mar 20, 2026 |
| Linux | python3-nltk Ubuntu 24.04.5 LTS (noble) | 3.8.1-1ubuntu0.1~esm2 | [python3-nltk 3.8.1-1ubuntu0.1~esm2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-nltk-3.8.1-1ubuntu0.1-esm2.md) | Mar 20, 2026 |
| Linux | python3-nltk Ubuntu 26.04.1 LTS (resolute) | 3.9.2-1ubuntu0.1~esm2 | [python3-nltk 3.9.2-1ubuntu0.1~esm2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-python3-nltk-3.9.2-1ubuntu0.1-esm2.md) | Mar 20, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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