This advisory has been withdrawn because it is a duplicate of GHSA-r6gq-whwq-mvg9. This link is maintained to preserve external references.
Original Description
NLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root. The vulnerability exists because path validation is lexical and does not account for symlink resolution, enabling attackers to place symlinks inside the corpus root to access files outside the intended boundary.