CVE-2026-0848: NLTK arbitrary code execution through StanfordSegmenter JAR loading

Summary

NLTK versions <=3.9.2 are affected by CVE-2026-0848, an improper input validation flaw in the StanfordSegmenter module. The module loads external Java .jar files without verification or sandboxing, and the JAR is executed via subprocess with unvalidated classpath input. An attacker who supplies or replaces the JAR can run arbitrary Java bytecode at import time, reachable through model poisoning, MITM attacks, or dependency poisoning.

Mitigation

The source does not state a fix yet. Check the original advisory for updates.

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