VYPR
High severity8.8NVD Advisory· Published Feb 18, 2026· Updated Jul 15, 2026

CVE-2025-14009

CVE-2025-14009

Description

A critical vulnerability exists in the NLTK downloader component of nltk/nltk, affecting all versions. The _unzip_iter function in nltk/downloader.py uses zipfile.extractall() without performing path validation or security checks. This allows attackers to craft malicious zip packages that, when downloaded and extracted by NLTK, can execute arbitrary code. The vulnerability arises because NLTK assumes all downloaded packages are trusted and extracts them without validation. If a malicious package contains Python files, such as __init__.py, these files are executed automatically upon import, leading to remote code execution. This issue can result in full system compromise, including file system access, network access, and potential persistence mechanisms.

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Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
nltkPyPI
< 3.9.33.9.3

Affected products

16

Patches

Vulnerability mechanics

References

11

News mentions

0

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