CVE-2026-12372Public exploitNetwork attack vectorHinoki check available

SSRF via shared-address-space validation gap

Published Aug 9, 2026 · Updated Aug 9, 2026

SSRF in NLTK 3.9.4 and its develop branch allows remote attackers to reach RFC 6598 hosts through network-loading helpers. validate_network_url accepts 100.64.0.0/10 addresses because its ipaddress checks reject private addresses and selected categories but not shared space. Reachability requires attacker influence over a URL used by a strict-mode application; the result is request-based exposure of non-public infrastructure, not code execution.

CVSS severity3.7
Low
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

SSRF in NLTK 3.9.4 and its develop branch allows remote attackers to reach RFC 6598 hosts through network-loading helpers. validate_network_url accepts 100.64.0.0/10 addresses because its ipaddress checks reject private addresses and selected categories but not shared space. Reachability requires attacker influence over a URL used by a strict-mode application; the result is request-based exposure of non-public infrastructure, not code execution.

The record

CVE
CVE-2026-12372
Published
Aug 9, 2026
Updated
Aug 9, 2026
Vendor
NLTK Project
Product
NLTK
Classifications
CWE-918
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=latest

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

NLTK Project · NLTKversion=unspecified <=latest

Published CVSS scores

3.7huntr.devCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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