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CVE-2025-14009

Nltk remote code execution

8.8 HIGHPublic exploitEPSS 0.95%
  1. Published18 Feb 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Nltk< 3.9.3

Remediation

Fixed in
Nltk≥ 3.9.3

References

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Frequently asked

Is CVE-2025-14009 being actively exploited?

CVE-2025-14009 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.95%.

How severe is CVE-2025-14009?

CVE-2025-14009 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 0.95% probability of exploitation.

Which products are affected by CVE-2025-14009?

Affected products include Nltk.

How do I fix CVE-2025-14009?

Upgrade affected software to a fixed version, for example Nltk 3.9.3 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-14009 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.