CVE-2026-12243 Path Traversal via Percent-Encoding in nltk.data.find() and nltk.data.load()

NLTK version 3.9.4 is vulnerable to a path traversal attack due to an incomplete fix for GitHub Issue 3504. The UNSAFENOPROTOCOLRE regex in nltk/data.py checks for literal ../ sequences but fails to account for percent-encoded traversal sequences such as ..%2f. The url2pathname function decodes...