---
id: CVE-2026-109956
title: >-
  NLTK through 3.10.3 contains a path traversal vulnerability in WekaClassifier
  that allows attackers to bypass nltk.pathsec containment by supplying
  unvalidated model paths
summary: >-
  NLTK through 3.10.3 contains a path traversal vulnerability in WekaClassifier
  that allows attackers to bypass nltk.pathsec containment by supplying
  unvalidated model paths. Attackers controlling the model_filename or model
  argument can m…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L'
cwe:
  - CWE-22
published: '2026-10-13'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T14:17:34.520'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-109956'
references:
  - url: 'https://github.com/nltk/nltk/security/advisories/GHSA-j456-xh4h-cpf2'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/nltk-through-3.10.3-path-traversal-via-wekaclassifier-model-path
    label: disclosure@vulncheck.com
tags:
  - nvd
ingestedAt: '2026-10-13T14:29:01.855Z'
---

## Overview

NLTK through 3.10.3 contains a path traversal vulnerability in WekaClassifier that allows attackers to bypass nltk.pathsec containment by supplying unvalidated model paths. Attackers controlling the model_filename or model argument can make the weka JVM write files via -d or probe files via -l outside allowed data roots.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.