wummel patool up to 4.0.4 Archive py_tarfile.py safe_extract path traversal

Summaryinfo

A vulnerability described as critical has been identified in wummel patool up to 4.0.4. This issue affects the function safe_extract in the library patoolib/programs/py_tarfile.py of the component Archive Handler. The manipulation results in path traversal. This vulnerability is known as CVE-2026-29509. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical has been found in wummel patool up to 4.0.4. Affected is the function safe_extract in the library patoolib/programs/py_tarfile.py 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:

Patool before 4.0.5 contains a path traversal vulnerability in the safe_extract() function in patoolib/programs/py_tarfile.py when running on Python before 3.12, where the is_within_directory() helper uses os.path.commonprefix() for character-level string comparison instead of path-level comparison, allowing a crafted archive member path to bypass the containment check. Attackers can supply a malicious archive with specially crafted member paths to write arbitrary files.

The weakness was published by Codeant Ai Security. The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-29509 since 03/04/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1006.

Upgrading to version 4.0.5 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-39879). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

• wummel

Name

• patool

Version

• 4.0.0
• 4.0.1
• 4.0.2
• 4.0.3
• 4.0.4

Website

• Product: https://github.com/wummel/patool/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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