NLTKGHSA-cgvx-9447-vcch

ntlk unsafe deserialization vulnerability

High7.5CVE-2024-39705 · Published Jun 28, 2024 · updated Sep 10, 2026

Affected versions

Package	Affected	Fixed in
nltk PyPI	< 3.9	3.9

Details and references

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.

CVSS 3.1: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Severity from: GitHub (reviewed advisory)
Weakness: CWE-300, CWE-502
Also known as: CVE-2024-39705, PYSEC-2024-167

More NLTK advisories

All NLTK

Date	Advisory	Severity	Fixed in
Feb 18	NLTK has a Zip Slip Vulnerability CVE-2025-14009Critical10.0fixed in 3.9.3	Critical10.0	3.9.3
Mar 4	NLTK has a Path Traversal issue CVE-2026-0847High8.6no fix yet	High8.6	No fix yet
Mar 5	NLTK versions <=3.9.2 are vulnerable to arbitrary code execution due to improper input validation in the StanfordSegmenter module. The module dynamically loads external Java .jar files without verification or sandboxing. An attacker can supply or replace the JAR file, enabling the execution of arbit CVE-2026-0848Critical10.0fixed in 3.9.3	Critical10.0	3.9.3
Mar 9	NLTK has Arbitrary File Read via Absolute Path Input in nltk.util.filestring() CVE-2026-0846High8.6fixed in 3.9.3	High8.6	3.9.3
Mar 18	Natural Language Toolkit (NLTK) has unbounded recursion in JSONTaggedDecoder.decode_obj() may cause DoS CVE-2026-66393Mediumfixed in 3.9.4	Medium	3.9.4
Mar 18	Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in nltk CVE-2026-33230Medium6.1fixed in 3.9.4	Medium6.1	3.9.4

Affected versions

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