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CRITICAL

CVE-2025-14009

CVSS v3

10

CRITICAL

EPSS Score

1.0 %

exploit probability, as of 2026-10-16

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • nltkPyPIall versions · fixed in 3.9.3

Vendor advisories

  • CVE-2025-14009 Red Hat Product Security6 products fixed · 5 known affected

    nltk: Zip Slip Vulnerability in nltk Leading to Code Execution

    openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9 as a component of OpenShift Lightspeed · openshift-lightspeed/lightspeed-ocp-rag-rhel9 as a component of OpenShift Lightspeed · openshift-lightspeed/lightspeed-service-api-rhel9 as a component of OpenShift Lightspeed

  • RHSA-2026:10184 Red Hat Product Security6 products fixed

    Red Hat Security Advisory: RHOAI 2.25.5 - Red Hat OpenShift AI

Full record on NVD

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2026-02-18
Last Modified
2026-03-06

Frequently asked questions

What is 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.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.

Is CVE-2025-14009 actively exploited?

Active exploitation of CVE-2025-14009 has not been confirmed. Its EPSS score was 1.0% on 2026-10-16, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2025-14009?

CVE-2025-14009 has a CVSS v3 base score of 10 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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