Python CPython up to 3.14.x Archive tarfile.extractall path traversal

Summaryinfo

A vulnerability classified as critical was found in Python CPython up to 3.14.x. This vulnerability affects the function tarfile.extractall of the component Archive Handler. The manipulation results in path traversal. This vulnerability is reported as CVE-2026-11940. The attack can be launched remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Python CPython up to 3.14.x. It has been classified as critical. Affected is the function tarfile.extractall of the component Archive Handler. The manipulation with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

tarfile.extractall() with the 'data' or 'tar' filter could be bypassed by a crafted archive where a hardlink references a symlink stored at a deeper name than the hardlink itself.  The extraction fallback validated the symlink at it's archived location but recreated it at the hardlink's shallower path, letting a relative target the filter judged contained escape the destination directory.  This allowed a malicious tar archive to create a symlink pointing outside the destination, enabling out-of-destination file reads or writes. This was an incomplete fix of CVE-2025-4330.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-11940 since 06/10/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1006 by the MITRE ATT&CK project.

Upgrading to version 3.15.0 eliminates this vulnerability. Applying the patch 27dd970bf6b17ebca7c8ed486a40ab043ed7af8f is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Programming Language Software

Vendor

• Python

Name

• CPython

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10
• 3.11
• 3.12
• 3.13
• 3.14

License

• open-source

Website

• Product: https://github.com/python/cpython/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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