CVE-2026-4426

Name	CVE-2026-4426
Description	A flaw was found in libarchive. An Undefined Behavior vulnerability exists in the zisofs decompression logic, caused by improper validation of a field (`pz_log2_bs`) read from ISO9660 Rock Ridge extensions. A remote attacker can exploit this by supplying a specially crafted ISO file. This can lead to incorrect memory allocation and potential application crashes, resulting in a denial-of-service (DoS) condition.
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)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
libarchive (PTS)	bullseye	3.4.3-2+deb11u1	vulnerable
	bullseye (security)	3.4.3-2+deb11u3	vulnerable
	bookworm	3.6.2-1+deb12u3	vulnerable
	bookworm (security)	3.6.2-1+deb12u2	vulnerable
	trixie	3.7.4-4	vulnerable
	forky, sid	3.8.5-1	vulnerable

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

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

https://github.com/libarchive/libarchive/pull/2897