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Fencer Vulns
high 8.1

CVE-2026-33236 json

NLTK has a Downloader Path Traversal Vulnerability (AFO) - Arbitrary File Overwrite

published 2026-03-19 7 mo ago modified 2026-11-04 5 d ago also GHSA-469j-vmhf-r6v7 , PYSEC-2026-2237 , EUVD-2026-13887

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

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, the NLTK downloader does not validate the `subdir` and `id` attributes when processing remote XML index files. Attackers can control a remote XML index server to provide malicious values containing path traversal sequences (such as `../`), which can lead to arbitrary directory creation, arbitrary file creation, and arbitrary file overwrite. Commit 89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a patches the issue.

Patch / fix

  • pypi nltk 3.9.4
  • Red Hat Red Hat OpenShift AI 2.25 1776243238, 1776319185, 1783091175
  • Red Hat Red Hat OpenShift AI 3.3 1778262893, 1778263054, 1782471606
  • nltk Debian 14 3.10.0-1

debian advisories DEBIAN-CVE-2026-33236

  • nltk Ubuntu Pro 14.04 LTS 2.0~b9-0ubuntu4.1~esm6
  • nltk Ubuntu Pro 16.04 LTS 3.1-1ubuntu0.1+esm4
  • nltk Ubuntu Pro 18.04 LTS 3.2.5-1ubuntu0.1+esm4
  • nltk Ubuntu Pro 20.04 LTS 3.4.5-2ubuntu0.1~esm4
  • nltk Ubuntu Pro 22.04 LTS 3.7-1ubuntu0.1~esm2
  • nltk Ubuntu Pro 24.04 LTS 3.8.1-1ubuntu0.1~esm2
  • nltk Ubuntu Pro 26.04 LTS 3.9.2-1ubuntu0.1~esm2

ubuntu advisories UBUNTU-CVE-2026-33236

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-33236 updated cvss 8.1

nltk: NLTK: Arbitrary file overwrite and creation via path traversal in XML index files

  • Red Hat Lightspeed Core lightspeed-core/rag-tool-rhel9, lightspeed-core/lightspeed-stack-rhel9
    affected: workaround, no fix available
  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9, openshift-lightspeed/lightspeed-service-api-rhel9, openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9 Red Hat Ansible Automation Platform 2 ansible-automation-platform-26/de-supported-rhel9, ansible-automation-platform-26/ee-supported-rhel9, ansible-automation-platform-25/lightspeed-chatbot-rhel8
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-llama-stack-core-rhel9
    affected: workaround, no fix available
  • Red Hat OpenShift AI 2.25 rhoai 1776243238, rhoai 1776319185, rhoai/odh-ta-lmes-job-rhel9 1783091175
    fixed: vendor fix RHSA-2026:10184
  • Red Hat OpenShift AI 3.3 rhoai 1778262893, rhoai 1778263054, rhoai/odh-trustyai-nemo-guardrails-server-rhel9 1782471606
    fixed: vendor fix RHSA-2026:19712
  • Red Hat Ansible Automation Platform 2 ansible-automation-platform/ee-minimal-rhel8, ansible-automation-platform/ee-minimal-rhel9, ansible-automation-platform-24/de-minimal-rhel8, ansible-automation-platform-24/de-minimal-rhel9, ansible-automation-platform-24/ee-minimal-rhel8, ansible-automation-platform-24/ee-minimal-rhel9, +20 more Red Hat OpenShift AI 2.25 rhoai 1775144403, rhoai 1776243157, rhoai 1776243163, rhoai 1776243192, rhoai 1776243217, rhoai 1776243229, +144 more Red Hat OpenShift AI 3.3 rhoai 1778239104, rhoai 1778262829, rhoai 1778262856, rhoai 1778262907, rhoai 1778262952, rhoai 1778262982, +156 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/nltk/nltk/security/advisories/GHSA-469j-vmhf-r6v7 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
CISA ADP 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
OSV 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

Affected packages

ecosystem package affected fixed in
pypi nltk
<3.9.4
3.9.4

Affected products

  • nltk nltk
  • Red Hat Red Hat OpenShift AI 2.25
  • Red Hat Red Hat OpenShift AI 3.3
  • Red Hat Lightspeed Core
  • Red Hat OpenShift Lightspeed
  • Red Hat Red Hat Ansible Automation Platform 2
  • Red Hat Red Hat OpenShift AI (RHOAI)

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.