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CVE

CVE-2026-33231

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research a

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. In versions 3.9.3 and prior, nltk.app.wordnet_app allows unauthenticated remote shutdown of the local WordNet Browser HTTP server when it is started in its default mode. A simple GET /SHUTDOWN%20THE%20SERVER request causes the process to terminate immediately via os._exit(0), resulting in a denial of service.

Commit bbaae83db86a0f49e00f5b0db44a7254c268de9b patches the issue.

HIGH · CVSS 7.5 EPSS 0.0002
Act now
  • Public exploit or PoC is available
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-306Missing Authentication for Critical Function
▤

Affected Products & Versions

1
nltk<= 3.9.3
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
PyPI nltk HIGH fixed in 3.9.4
⚠

Public Exploits & PoCs

1
pocgithub.com · GHSA-jm6w-m3j8-898ggithub.com
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD20 Mar 2026 · 11:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
poc
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

2
usnUSN-8302-1
rhsaRHSA-2026:19712Important
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/nltk/nltk/commit/bbaae83db86a0f49e00f5b0db44a7254c268de9bPatch
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