Bug 2370016 (CVE-2025-4517)

Summary: CVE-2025-4517 python: cpython: Arbitrary writes via tarfile realpath overflow
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: bbrownin, dfreiber, drow, jburrell, ljawale, luizcosta, nweather, rbobbitt, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the CPython tarfile module. This vulnerability allows arbitrary filesystem writes outside the extraction directory via extracting untrusted tar archives using the TarFile.extractall() or TarFile.extract() methods with the extraction filter parameter set to "data" or "tar".
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2370025    
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Description OSIDB Bzimport 2025-06-03 14:01:35 UTC 
Allows arbitrary filesystem writes outside the extraction directory during extraction with filter="data".


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.