CVE-2025-14009

Published Feb 18, 2026

Last updated 2 months ago

CVSS high 8.8
Ubuntu

Overview

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.
Source
security@huntr.dev
NVD status
Modified
Products
nltk

Risk scores

CVSS 3.1

Type
Secondary
Base score
8.8
Impact score
5.9
Exploitability score
2.8
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

CVSS 3.0

Type
Secondary
Base score
10
Impact score
6
Exploitability score
3.9
Vector string
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Severity
CRITICAL

Weaknesses

security@huntr.dev
CWE-94
0b0ca135-0b70-47e7-9f44-1890c2a1c46c
CWE-94

Social media

Hype score
Not currently trending

  1. BREAKING: Critical NLTK bug CVE-2025-14009 in Ubuntu 14.04-24.04 allows arbitrary code execution via malicious zip files, users urged to update packages immediately. https://t.co/YUWRnaudAa

    @threatcluster

    28 Apr 2026

    203 Impressions

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  2. 🔴 NLTK, Code Injection, #CVE-2025-14009 (Critical) https://t.co/JAXvC0RQmW

    @dailycve

    7 Mar 2026

    92 Impressions

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  3. `NLTK` is vulnerable to a path traversal flaw (CVE-2025-14009) in its downloader, enabling arbitrary file writes via crafted zip archives. Mitigation details: #nltk #infosec #pathtraversal https://t.co/JQw9mXXq0y

    @pulsepatchio

    20 Feb 2026

    36 Impressions

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  4. A path traversal vulnerability (CVE-2025-14009) affects the `NLTK` downloader, allowing arbitrary file writes. Evaluate `nltk` use with untrusted data. #Python #PathTraversal #infosec https://t.co/gmFoLpCv9H

    @pulsepatchio

    20 Feb 2026

    40 Impressions

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  5. CVE-2025-14009 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.ext… https://t.co/4KfoSbl5bF

    @CVEnew

    18 Feb 2026

    126 Impressions

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  6. 🔴 CVE-2025-14009 - Critical 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 per... https://t.co/lOegNOoKGN https://t.co/wUKtQpU050

    @TheHackerWire

    18 Feb 2026

    49 Impressions

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Configurations

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References

Sources include official advisories and independent security research.