CVE-2026-12372

Description

A Server-Side Request Forgery (SSRF) vulnerability exists in nltk/nltk versions 3.9.4 and the current develop branch. The `nltk.pathsec.validate_network_url()` function, intended to prevent SSRF by rejecting internal network addresses, fails to reject IPs in the RFC 6598 shared address space (`100.64.0.0/10`). This occurs because Python's `ipaddress` module does not classify such addresses as `is_private` or `is_global`, and the current guard only checks `is_private` and a few explicit categories. An attacker who can influence a URL passed to NLTK's network-loading helpers can exploit this vulnerability to make a strict-mode application send requests to shared-address-space hosts, potentially exposing non-public infrastructure reachable from the application host. The impact is limited to SSRF-style confidentiality exposure, with no code execution claimed.

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Produits concernés

• nltk/nltk
• Nltk nltk

Scores CVSS

Faiblesses (CWE)

• CWE-918

Références

• https://huntr.com/bounties/2911b643-571c-42e4-b0c2-9a1fa6f491db Permissions Required
• https://huntr.com/bounties/2911b643-571c-42e4-b0c2-9a1fa6f491db Permissions Required

Ailleurs

• NVD
• CVE.org
• CIRCL Vulnerability-Lookup
• CERT-FR
• GitHub Advisories