HIGH CVSS 8.8
Published: 2026-02-18

CVE-2025-14009

nltk nltk Security Advisory (CVE-2025-14009)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2025-14009 impacting nltk nltk. Evaluated with CVSS Base Score of 8.8 (HIGH).

Original NVD Description

Source: NIST NVD
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.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
Low (PR:L)
Standard user access required
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
High (C:H)
Total information disclosure
Integrity
High (I:H)
Total modification of target system
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product nltk / nltk
Affected Versions *
Weakness Enumeration CWE-94

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2025-14009 impacting nltk nltk.

⚡ Nuclei Detection Template (YAML) cve-2025-14009.yaml
id: cve-2025-14009

info:
  name: nltk nltk - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2025-14009 affecting nltk nltk.
    Evaluation: A critical vulnerability exists in the NLTK downloader component of nltk/nltk, affecting all versions. The _unzip_iter function in nltk/downloader.py ...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2025-14009
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 8.8
    cve-id: CVE-2025-14009
    cwe-id: CWE-94
  tags: cve,cve-2025-14009,nltk,nltk,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "nltk"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2025-14009.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2025-14009
# Target: nltk nltk | CVSS: 8.8 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2025-14009 (nltk nltk)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against nltk nltk scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2025-14009.sh
# Recommended Remediation & Patching Commands for CVE-2025-14009
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install nltk 2>/dev/null || \
sudo dnf upgrade nltk 2>/dev/null || \
sudo yum update nltk

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i nltk 2>/dev/null || rpm -qa | grep -i nltk

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2025-14009 in nltk nltk?

Review vendor-specific security notices and update nltk nltk packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2025-14009?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2025-14009?

CVE-2025-14009 is classified with a CVSS 3.1 Base Score of 8.8 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.8
HIGH SEVERITY
CVE ID CVE-2025-14009
Weakness CWE-94
Vendor nltk
Product nltk
Published 2026-02-18
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H