CVEvulnerability

CVE-2026-12372

3.7 LOW Published 2026-08-09 Modified 2026-10-23 Official page ↗
Status
Analyzed
Published
2026-08-09
Last modified
2026-10-23
Assigner
[email protected]
CVSS 3.0 ([email protected])
3.7 LOW — CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Weaknesses
CWE-918

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.

Affected configurations

• nltk nltk 3.9.4

Related

Weakness · CWE (1)

  • CWE-918 Server-Side Request Forgery weakness

References