CVE-2026-66484

Name	CVE-2026-66484
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. This issue has been fixed in commit e2b9cbdd3354d2b1569b7390d1bc15c1930559ad
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1144387

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
cpio (PTS)	bullseye	2.13+dfsg-7.1~deb11u1	vulnerable
	bookworm	2.13+dfsg-7.1	vulnerable
	trixie	2.15+dfsg-2	vulnerable
	forky, sid	2.15+dfsg-2.1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
cpio	source	(unstable)	(unfixed)			1144387

Notes

[trixie] - cpio <no-dsa> (Minor issue)
[bookworm] - cpio <postponed> (Minor issue)
[bullseye] - cpio <postponed> (Minor issue)
https://cert.pl/en/posts/2026/08/CVE-2026-66484
Fixed by: https://git.savannah.gnu.org/cgit/cpio.git/commit/?id=e2b9cbdd3354d2b1569b7390d1bc15c1930559ad