# CVE-2026-33230: nltk: NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting researc...

CVE-2026-33230 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: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-33230
- Priority: Routine
- CVSS: 6.1 (medium)
- EPSS: 0.0034
- 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` 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 local WordNet Browser server and can lead to script execution in the browser origin of that application. Commit 1c3f799607eeb088cab2491dcf806ae83c29ad8f fixes the issue.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | nltk Debian 14 | 3.10.0-1 | [DEBIAN-CVE-2026-33230](https://patchblox.com/security/data/fix/linux/debian-cve-2026-33230.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 2026-11-08T19:12:23Z 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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