CVE-2025-14009
CRITICAL
GHSA-7p94-766c-hgjp
CVSS Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Lifecycle Timeline
4Description
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.
Analysis
Critical code execution vulnerability in NLTK (Natural Language Toolkit) downloader component. The _unzip_iter function can be exploited to achieve arbitrary code execution through crafted downloads. CVSS 10.0, EPSS 0.57%. PoC available.
Technical Context
CWE-94 code injection in NLTK's _unzip_iter function within the downloader. All NLTK versions are affected. The downloader processes ZIP files in a way that allows code execution.
Affected Products
['NLTK (all versions)']
Remediation
Update NLTK to a patched version. Verify integrity of downloaded NLTK data. Use trusted, pinned data sources.
Priority Score
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External POC / Exploit Code
Leaving vuln.today