GNU Cpio up to 2.15 Tar Archive Extraction link_to_name path traversal

Summaryinfo

A vulnerability was found in GNU Cpio up to 2.15 and classified as critical. This affects the function link_to_name of the component Tar Archive Extraction. The manipulation results in path traversal. This vulnerability is cataloged as CVE-2026-66484. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in GNU Cpio up to 2.15. It has been classified as critical. Affected is the function link_to_name of the component Tar Archive Extraction. 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:

GNU cpio contains a Path Traversal vulnerability in its tar archive extraction functionality. When extracting a tar archive in copy-in mode with the --no-absolute-filenames option, the extracted file name is normalized but the tar hard-link target is passed to the link_to_name function without equivalent sanitization before calling link function. A tar archive provided by an attacker, containing a hard-link entry whose linkname is set to an absolute path outside the extraction directory, can cause cpio to create a hard link to an existing file outside the intended extraction directory, breaking the expected guarantee of --no-absolute-filenames and allowing archive-controlled linkage to external files. This issue has been fixed in commit e2b9cbdd3354d2b1569b7390d1bc15c1930559ad

The advisory is shared for download at cert.pl. This vulnerability is traded as CVE-2026-66484 since 07/27/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. 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.

Applying the patch e2b9cbdd3354d2b1569b7390d1bc15c1930559ad is able to eliminate this problem.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-2722). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Open Source cpio

Productinfo

Vendor

• GNU

Name

• Cpio

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15

License

• open-source

Website

• Vendor: https://www.gnu.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

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

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