NLTK has unauthenticated remote shutdown in nltk.app.wordnet_app
Summary
| CVE | CVE-2026-33231 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-20 23:16:46 UTC |
| Updated | 2026-07-10 12:16:40 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.008750000 probability, percentile 0.547240000 (date 2026-07-12)
Problem Types: CWE-306 | CWE-306 CWE-306: Missing Authentication for Critical Function | CWE-306 Missing Authentication for Critical Function
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | ADP | CVSS | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | [email protected] | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | DECLARED | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Nltk | Nltk | affected <= 3.9.3 | Not specified |
| ADP | Red Hat | Red Hat OpenShift AI 2.25 | Not specified | Not specified |
| ADP | Red Hat | Red Hat OpenShift AI 3.3 | Not specified | Not specified |
| ADP | Red Hat | Lightspeed Core | Not specified | Not specified |
| ADP | Red Hat | OpenShift Lightspeed | Not specified | Not specified |
| ADP | Red Hat | Red Hat Ansible Automation Platform 2 | Not specified | Not specified |
| ADP | Red Hat | Red Hat OpenShift AI RHOAI | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33231.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-33231 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:24977 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| github.com/nltk/nltk/commit/bbaae83db86a0f49e00f5b0db44a7254c268de9b | [email protected] | github.com | Patch |
| access.redhat.com/errata/RHSA-2026:37275 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| github.com/nltk/nltk/security/advisories/GHSA-jm6w-m3j8-898g | [email protected] | github.com | Exploit, Vendor Advisory |
| access.redhat.com/errata/RHSA-2026:19712 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-03-20T23:02:37.298Z | Reported to Red Hat. |
| ADP | 2026-03-20T22:45:40.784Z | Made public. |
Solutions
ADP: RHSA-2026:24977: Red Hat OpenShift AI 2.25
ADP: RHSA-2026:19712: Red Hat OpenShift AI 3.3
ADP: RHSA-2026:37275: Red Hat OpenShift AI 3.3
Workarounds
ADP: To mitigate this vulnerability, ensure that the NLTK WordNet Browser HTTP server (`nltk.app.wordnet_app`) is not exposed to untrusted networks. If the WordNet Browser functionality is not required, disable or remove the component. For deployments where the server is necessary, configure firewall rules to restrict access to trusted hosts only. A service restart may be required for changes to take effect.