CVE-2025-14009

CVE-2025-14009 is a high-severity vulnerability in Nltk with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-94.

Key facts

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.

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.
How severe is CVE-2025-14009?
CVE-2025-14009 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-14009 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-14009?
CVE-2025-14009 affects Nltk. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-14009?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-14009 have an EU (EUVD) identifier?
Yes. CVE-2025-14009 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-207820.
When was CVE-2025-14009 published?
CVE-2025-14009 was published on 2026-02-18 and last updated on 2026-07-15.

References

Affected products (1)

More vulnerabilities in Nltk

All CVEs affecting Nltk →

Other CWE-94 (Code Injection) vulnerabilities

Browse all CWE-94 (Code Injection) vulnerabilities →