kovidgoyal calibre up to 9.2.x utils/zipfile.py ZipFile.extractall path traversal

Summaryinfo

A vulnerability described as critical has been identified in kovidgoyal calibre up to 9.2.x. Affected by this vulnerability is the function ZipFile.extractall of the file utils/zipfile.py. Such manipulation leads to path traversal. This vulnerability is uniquely identified as CVE-2026-26064. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in kovidgoyal calibre up to 9.2.x and classified as critical. Affected by this issue is the function ZipFile.extractall of the file utils/zipfile.py. The manipulation with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to 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. Impacted is confidentiality, integrity, and availability. CVE summarizes:

calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Versions 9.2.1 and below contain a Path Traversal vulnerability that allows arbitrary file writes anywhere the user has write permissions. On Windows, this leads to Remote Code Execution by writing a payload to the Startup folder, which executes on next login. Function extract_pictures only checks startswith('Pictures'), and does not sanitize '..' sequences. calibre's own ZipFile.extractall() in utils/zipfile.py does sanitize '..' via _get_targetpath(), but extract_pictures() bypasses this by using manual zf.read() + open(). This issue has been fixed in version 9.3.0.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-26064 since 02/10/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1006.

The vulnerability scanner Nessus provides a plugin with the ID 299678 (Linux Distros Unpatched Vulnerability : CVE-2026-26064), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 9.3.0 eliminates this vulnerability. Applying the patch e1b5f9b45a5e8fa96c136963ad9a1d35e6adac62 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.

The vulnerability is also documented in the vulnerability database at Tenable (299678). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

• kovidgoyal

Name

• calibre

Version

• 9.0
• 9.1
• 9.2

License

• open-source

Website

• Product: https://github.com/kovidgoyal/calibre/

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

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