Bug 2370014 (CVE-2025-4330)

Summary: CVE-2025-4330 cpython: Extraction filter bypass for linking outside extraction directory
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: bbrownin, dfreiber, drow, jburrell, ljawale, luizcosta, nweather, rbobbitt, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in CPython's tarfile module. This vulnerability allows bypassing of extraction filters, enabling symlink traversal outside the intended extraction directory and potential modification of file metadata via malicious tar archives using TarFile.extractall() or TarFile.extract() with the filter="data" or filter="tar" parameters. This issue leads to potentially overwriting or modifying system files and metadata.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2370024    
Bug Blocks:    

Description OSIDB Bzimport 2025-06-03 14:01:25 UTC 
Allows the extraction filter to be ignored, allowing symlink targets to point outside the destination directory, and the modification of some file metadata.


You are affected by this vulnerability if using the tarfile module to extract untrusted tar archives using TarFile.extractall() or TarFile.extract() using the filter= parameter with a value of "data" or "tar". See the tarfile  extraction filters documentation https://docs.python.org/3/library/tarfile.html#tarfile-extraction-filter  for more information. Only Python versions 3.12 or later are affected by these vulnerabilities, earlier versions don't include the extraction filter feature.

Note that for Python 3.14 or later the default value of filter= changed from "no filtering" to `"data", so if you are relying on this new default behavior then your usage is also affected.

Note that none of these vulnerabilities significantly affect the installation of source distributions which are tar archives as source distributions already allow arbitrary code execution during the build process. However when evaluating source distributions it's important to avoid installing source distributions with suspicious links.