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.

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-8214-1 advisory.

    It was discovered that NLTK incorrectly handled file extraction when opening a maliciously crafted zip     file. An attacker could possibly use this issue to create or overwrite files on the system and execute     arbitrary code.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - 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. (CVE-2025-14009)

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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. (CVE-2025-14009)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
310738	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : NLTK vulnerability (USN-8214-1)	Nessus	Ubuntu Local Security Checks	Local	critical
437996	SCA: security update for nltk (GHSA-7p94-766c-hgjp)	Tenable Cloud Security	SCA Checks	Local	high
437996	SCA: security update for nltk (GHSA-7p94-766c-hgjp)	Tenable Self-Hosted Container Security	SCA Checks	Local	high
299599	Linux Distros Unpatched Vulnerability : CVE-2025-14009	Nessus	Misc.	Local	high

Detections

Analytics

CVE-2025-14009

high

Tenable Plugins

critical

high

high

high