Withdrawn by the publisher.

Affected: PyPI: nltk

## Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-r53h-rw34-8h97. This link is maintained to preserve external references.

## Original Description NLTK before 3.10.4 contains a denial of service vulnerability in Tree.chomsky_normal_form that allows remote attackers to exhaust CPU through quadratic-time right-factor binarization using list.pop(0). Attackers can supply a wide flat treebank tree parsed by Tree.fromstring to force tens of seconds of single-threaded CPU consumption, blocking the processing thread.