PYSEC-2026-3583 Natural Language Toolkit (NLTK): DNS-rebinding SSRF filter bypass in nltk.pathsec.urlopen (nltk.download / nltk.data.load) defeats ENFORCE mode

Summary nltk.pathsec provides an SSRF filter that NLTK documents as a security control, blocking loopback, private, link-local, and multicast ranges including obfuscated forms and recommending strict ENFORCE mode for security-sensitive environments. The filter is bypassable by DNS rebinding:...