CVE-2026-12372 (GCVE-0-2026-12372)

Vulnerability from cvelistv5 – Published: 2026-08-09 22:45 – Updated: 2026-08-12 17:48
VLAI
Title
Server-Side Request Forgery (SSRF) in nltk/nltk
Summary
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.
Severity
3.7 (Low)
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-12 17:45 UTC
CWE
  • CWE-918 - Server-Side Request Forgery (SSRF)
Assigner
@huntr_ai CNA under the mitre root
CNA scorecard C 65/100 over 40 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
nltk nltk/nltk Affected: unspecified , ≤ latest (custom)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

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