CVE-2025-14009

Published Feb 18, 2026

Last updated 3 months ago

CVSS critical 10.0

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: Analyzed
Products: nltk

Risk scores

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

Hype score: Not currently trending

Configurations

[
  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "22061B61-87EB-4006-8152-23CD3514C2AE",
            "versionEndExcluding": "3.9.3",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ]
  }
]

References

Sources include official advisories and independent security research.

Overview

Risk scores

CVSS 3.0

Weaknesses

Social media

Configurations

Related CVEs

References