Bug 2513087 (CVE-2026-66484)

Summary: CVE-2026-66484 cpio: GNU cpio: Path Traversal allows creating hard links outside intended directory via malicious tar archives.
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in GNU cpio. This vulnerability, known as Path Traversal, occurs during the extraction of tar archives in copy-in mode when the `--no-absolute-filenames` option is used. A remote attacker could craft a malicious tar archive containing a hard-link entry with an absolute path. This could allow cpio to create a hard link to an existing file outside the intended extraction directory, bypassing security controls and potentially leading to unauthorized file system modifications.
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Bug Depends On: 2513960    
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Description OSIDB Bzimport 2026-08-10 10:32:00 UTC 
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