CVE-2026-12372 Server-Side Request Forgery (SSRF) in nltk/nltk

A Server-Side Request Forgery SSRF vulnerability exists in nltk/nltk versions 3.9.4 and the current develop branch. The nltk.pathsec.validatenetworkurl function, intended to prevent SSRF by rejecting internal network addresses, fails to reject IPs in the RFC 6598 shared address space 100.64.0.0/1...

CVE-2026-12372

A Server-Side Request Forgery (SSRF) exists in nltk/nltk versions 3.9.4 and the current develop branch. The function nltk.pathsec.validate_network_url() fails to reject IPs in RFC 6598 shared address space (100.64.0.0/10) because Python’s ipaddress classification does not mark such addresses as i...