nltk: NLTK versions <=3.9.2 are vulnerable to arbitrary code execution due to improper input validation in the StanfordSegm...
CVE-2026-0848 is fixed in 3 products on 1 platform, first by DEBIAN-CVE-2026-0848, released March 5, 2026. It is not reported as exploited. Patch Radar priority: Urgent.
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 arises from the direct execution of the JAR file via subprocess with unvalidated classpath input, allowing malicious classes to execute when loaded by the JVM.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| nltk · Debian 14 | 3.9.3-1 | DEBIAN-CVE-2026-0848 | Mar 5, 2026 |
| python-nltk · Ubuntu 18.04.6 LTS (bionic) | 3.2.5-1ubuntu0.1+esm4 | python-nltk 3.2.5-1ubuntu0.1+esm4 | Mar 20, 2026 |
| python3-nltk · Ubuntu 18.04.6 LTS (bionic) | 3.2.5-1ubuntu0.1+esm4 | python3-nltk 3.2.5-1ubuntu0.1+esm4 | Mar 20, 2026 |
| python3-nltk · Ubuntu 20.04 LTS (focal) | 3.4.5-2ubuntu0.1~esm4 | python3-nltk 3.4.5-2ubuntu0.1~esm4 | Mar 20, 2026 |
| python3-nltk · Ubuntu 22.04.1 LTS (jammy) | 3.7-1ubuntu0.1~esm2 | python3-nltk 3.7-1ubuntu0.1~esm2 | Mar 20, 2026 |
| python3-nltk · Ubuntu 24.04.5 LTS (noble) | 3.8.1-1ubuntu0.1~esm2 | python3-nltk 3.8.1-1ubuntu0.1~esm2 | Mar 20, 2026 |
| python3-nltk · Ubuntu 26.04.1 LTS (resolute) | 3.9.2-1ubuntu0.1~esm2 | python3-nltk 3.9.2-1ubuntu0.1~esm2 | Mar 20, 2026 |
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