CVE-2025-4330: 
Python Interpreter vulnerability analysis and mitigation

CVE-2025-4330 is a high severity vulnerability affecting Python's tarfile module. The vulnerability allows the extraction filter to be ignored, enabling symlink targets to point outside the destination directory and the modification of some file metadata. This vulnerability affects Python versions 3.12 or later when using the tarfile module to extract untrusted tar archives using TarFile.extractall() or TarFile.extract() with the filter= parameter set to "data" or "tar". For Python 3.14 or later, where the default filter value changed from "no filtering" to "data", users relying on this default behavior are also affected (Python Security Announce).

The vulnerability occurs when the extraction filter is bypassed during tar archive extraction operations. The issue specifically affects the filter functionality introduced in Python 3.12, which was designed to provide security controls during archive extraction. The vulnerability has been assigned a CVSS v3.1 Base Score of 7.5 (HIGH) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N (NVD).

When exploited, this vulnerability allows attackers to bypass the intended security controls of the tarfile extraction filters. This can lead to symlink targets pointing outside the designated destination directory and unauthorized modification of file metadata. The vulnerability is particularly concerning when processing untrusted tar archives, as it could lead to unauthorized file system access beyond the intended extraction directory (Python Security Announce).

The recommended mitigation is to upgrade to a fixed version of Python or apply the available patches. For users unable to upgrade or patch, a workaround is available by implementing additional checks before extraction: reject all links containing parent directory segments (".."). A sample mitigation code has been provided that checks for insecure segments in link names before extraction (Python Security Announce, GitHub Gist).