CVE-2026-34743

Name	CVE-2026-34743
Description	XZ Utils provide a general-purpose data-compression library plus command-line tools. Prior to version 5.8.3, if lzma_index_decoder() was used to decode an Index that contained no Records, the resulting lzma_index was left in a state where where a subsequent lzma_index_append() would allocate too little memory, and a buffer overflow would occur. This issue has been patched in version 5.8.3.
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	1132497

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
xz-utils (PTS)	bullseye (security), bullseye	5.2.5-2.1~deb11u1	vulnerable
	bookworm, bookworm (security)	5.4.1-1	vulnerable
	trixie	5.8.1-1	vulnerable
	forky, sid	5.8.3-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
xz-utils	source	(unstable)	5.8.3-1			1132497

Notes

[trixie] - xz-utils <no-dsa> (Minor issue)
[bookworm] - xz-utils <no-dsa> (Minor issue)
[bullseye] - xz-utils <postponed> (Minor issue)
https://tukaani.org/xz/index-append-overflow.html
Fixed by: https://github.com/tukaani-project/xz/commit/c8c22869e780ff57c96b46939c3d79ff99395f87 (v5.8.3)