CVE-2025-14009
Publication date 18 February 2026
Last updated 29 April 2026
Ubuntu priority
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.
Why is this CVE high priority?
arbitrary code execution
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| nltk | 26.04 LTS resolute |
Fixed 3.9.2-1ubuntu0.1~esm1
|
| 25.10 questing |
Vulnerable
|
|
| 24.04 LTS noble |
Fixed 3.8.1-1ubuntu0.1~esm1
|
|
| 22.04 LTS jammy |
Fixed 3.7-1ubuntu0.1~esm1
|
|
| 20.04 LTS focal |
Fixed 3.4.5-2ubuntu0.1~esm3
|
|
| 18.04 LTS bionic |
Fixed 3.2.5-1ubuntu0.1+esm3
|
|
| 16.04 LTS xenial |
Fixed 3.1-1ubuntu0.1+esm3
|
|
| 14.04 LTS trusty |
Fixed 2.0~b9-0ubuntu4.1~esm5
|
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Get Ubuntu Pro 30-day free trialSeverity score breakdown
| Parameter | Value |
|---|---|
| Base score |
10.0 · Critical
|
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Changed |
| Confidentiality | High |
| Integrity impact | High |
| Availability impact | High |
| Vector | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H |
References
Related Ubuntu Security Notices (USN)
- USN-8214-1
- NLTK vulnerability
- 28 April 2026