GHSA-8MPW-7FPC-4GQJ NLTK: Pl196xCorpusReader has quadratic ReDoS on malformed TEI blocks

Summary Pl196xCorpusReader still parses whole TEI blocks with multiple lazy regexes over attacker-controlled text. A malformed file with many opening tags and no matching closing tags forces repeated rescans and produces quadratic CPU growth in public reader APIs. Details - Vulnerability type:...