Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-66484

Severity CVSS v4.0:
MEDIUM
Type:
CWE-22 Path Traversal
Publication date:
10/08/2026
Last modified:
10/08/2026

Description

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.<br /> <br /> This issue has been fixed in commit e2b9cbdd3354d2b1569b7390d1bc15c1930559ad

Impact

Vector 4.0
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 4.60 MEDIUM
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

Attack Vector (AV): Local
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): None
User Interaction (UI): Active
Confidentiality (VC): None
Integrity (VI): Low
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): Low
Availability (SA): None

Base Score 4.0
4.60
Severity 4.0
MEDIUM

References to Advisories, Solutions, and Tools