Directory Traversal Affecting cpio package, versions <2.15+dfsg-2.1ubuntu0.1


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.2% (9th percentile)

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  • Snyk IDSNYK-UBUNTU2604-CPIO-18741464
  • published18 Aug 2026
  • disclosed10 Aug 2026

Introduced: 10 Aug 2026

CVE-2026-66484  (opens in a new tab)
CWE-22  (opens in a new tab)

How to fix?

Upgrade Ubuntu:26.04 cpio to version 2.15+dfsg-2.1ubuntu0.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream cpio package and not the cpio package as distributed by Ubuntu. See How to fix? for Ubuntu:26.04 relevant fixed versions and status.

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

CVSS Base Scores

version 3.1