Read the docs
TI-2026-25650 Aliases CVE-2026-33231GHSA-jm6w-m3j8-898g

NLTK has unauthenticated remote shutdown in nltk.app.wordnet_app

Priority HIGH 72CWE-306Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 2 fixed, 4 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-306.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.01264 69th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial nltk (PyPI): 3.9.4Red Hat: 5 advisoriesRed Hat: 2 fixed, 4 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nltknltkup to 3.9.3—No fix listedCNA
—nltk (PyPI)before 3.9.43.9.4Patch availableGHSA-jm6w-m3j8-898g
  • nltk Vendornltk Affected up to 3.9.3 Fixed in — No fix listed CNA
  • nltk (PyPI) Vendor— Affected before 3.9.4 Fixed in 3.9.4 Patch available GHSA-jm6w-m3j8-898g

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*up to 3.9.3Vulnerablenltk
  • cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:* Versions up to 3.9.3 Vulnerable ·nltk

Remediation

  • Fix · GHSA-jm6w-m3j8-898g nltk (PyPI) Fixed in 3.9.4 Advisory →

Red Hat 5 advisories

  • RHSA-2026:73987 Released 2026-09-30 · Red Hat rating Critical
    RHOAI 3.3.7 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 3.3 registry.redhat.io/rhoai/odh-built-in-detector-rhel9, registry.redhat.io/rhoai/odh-dashboard-rhel9, registry.redhat.io/rhoai/odh-data-science-pipelines-argo-argoexec-rhel9 +47
  • RHSA-2026:65126 Released 2026-09-08 · Red Hat rating Important
    RHOAI 2.25.11 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 2.25 registry.redhat.io/rhoai/odh-built-in-detector-rhel9, registry.redhat.io/rhoai/odh-caikit-tgis-serving-rhel9, registry.redhat.io/rhoai/odh-dashboard-rhel9 +47
  • RHSA-2026:37275 Released 2026-07-09 · Red Hat rating Critical
    RHOAI 3.3.5 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 3.3 registry.redhat.io/rhoai/odh-dashboard-rhel9, registry.redhat.io/rhoai/odh-data-science-pipelines-operator-controller-rhel9, registry.redhat.io/rhoai/odh-feast-operator-rhel9 +45
Show 2 more Red Hat advisories
  • RHSA-2026:24977 Released 2026-06-10 · Red Hat rating Important
    RHOAI 2.25.7 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 2.25 registry.redhat.io/rhoai/odh-caikit-nlp-rhel9, registry.redhat.io/rhoai/odh-caikit-tgis-serving-rhel9, registry.redhat.io/rhoai/odh-dashboard-rhel9 +34
  • RHSA-2026:19712 Released 2026-05-20 · Red Hat rating Critical
    RHOAI 3.3.3 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 3.3 registry.redhat.io/rhoai/odh-built-in-detector-rhel9, registry.redhat.io/rhoai/odh-dashboard-rhel9, registry.redhat.io/rhoai/odh-data-science-pipelines-argo-argoexec-rhel9 +33

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Lightspeed CoreAffectedNo fix yet
OpenShift LightspeedAffectedNo fix planned: Will not fix
Red Hat Ansible Automation Platform 2AffectedNo fix yet
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet
Red Hat OpenShift AI 2.25Fixed RHSA-2026:24977, RHSA-2026:65126
Red Hat OpenShift AI 3.3Fixed RHSA-2026:19712, RHSA-2026:37275, RHSA-2026:73987
Not affected: 4 products
  • OpenShift Lightspeed
  • Red Hat Ansible Automation Platform 2
  • Red Hat OpenShift AI 2.25
  • Red Hat OpenShift AI 3.3

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-33231
  2. 2026-10-03 Alias added: GHSA-jm6w-m3j8-898g
  3. 2026-10-07 Fix available: RHSA-2026:73987 · Red Hat

References

Exploit 1

Patch 1

Advisory 1

Other 1

  • TI-2026-00629 Arbitrary Code Execution in NLTK StanfordSegmenter via Untrusted JAR Loading CVSS 3.0CRITICAL 10.0
  • TI-2025-12800 Zip Slip Vulnerability in nltk/nltk Leading to Remote Code Execution CVSS 3.0CRITICAL 10.0
  • TI-2026-55173 NLTK before 3.10.3 JVM Argument Injection via Per-Call Options CVSS 4.0CRITICAL 9.3
  • TI-2026-55155 NLTK before 3.10.3 Remote Code Execution via Unsafe Pickle Deserialization CVSS 4.0CRITICAL 9.3
  • TI-2026-56370 nltk PorterStemmer before 3.10.3 Quadratic-time DoS CVSS 4.0HIGH 8.7
  • TI-2026-55172 NLTK 3.10.2 Path Traversal via corpus-reader constructors CVSS 4.0HIGH 8.8
See all 41 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences