---
id: CVE-2024-39705
aliases:
  - GHSA-cgvx-9447-vcch
  - PYSEC-2024-167
title: ntlk unsafe deserialization vulnerability
summary: ntlk unsafe deserialization vulnerability
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'
vendor: nltk
product: nltk
ecosystem: pip
affected:
  - nltk < 3.9
patched:
  - nltk 3.9
published: '2024-06-28'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:50:15.193241968Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-cgvx-9447-vcch'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2024-39705'
  - url: 'https://github.com/nltk/nltk/issues/2522'
  - url: 'https://github.com/nltk/nltk/issues/3266'
  - url: >-
      https://github.com/nltk/nltk/commit/441aecb7d33014bd08672232c6c8bb69c2ceaba2
  - url: 'https://github.com/nltk/nltk'
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2024-167.yaml
  - url: >-
      https://www.vicarius.io/vsociety/posts/rce-in-python-nltk-cve-2024-39705-39706
tags:
  - osv
  - pip
epss: 0.01346
epssPercentile: 0.70223
ingestedAt: '2026-09-12T03:13:01.687Z'
---

## Overview

NLTK through 3.8.1 allows remote code execution if untrusted packages have pickled Python code, and the integrated data package download functionality is used. This affects, for example, averaged_perceptron_tagger and punkt.

## Affected packages

- `nltk < 3.9`

## Remediation

Upgrade to a patched release:

- `nltk 3.9`