CVE-2026-62430

Name	CVE-2026-62430
Description	Accesses to the CMOS memory contents are done using an indirect IO port pair. Therefore Xen needs to cache the guest chosen index, and one of the usages of the index didn't take the necessary locking to avoid concurrent changes. As a result, a guest could change the index after it being checked, causing a subsequent out-of-bound read access to the contents of an array.
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)
References	DSA-6424-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
xen (PTS)	bullseye	4.14.6-1	vulnerable
	bullseye (security)	4.14.5+94-ge49571868d-1	vulnerable
	bookworm, bookworm (security)	4.17.5+72-g01140da4e8-1	vulnerable
	trixie	4.20.2+37-g61ff35323e-0+deb13u1	vulnerable
	trixie (security)	4.20.3+127-gc42374a105-0+deb13u1	fixed
	forky, sid	4.20.3+127-gc42374a105-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin
xen	source	bullseye	(unfixed)	end-of-life
xen	source	trixie	4.20.3+127-gc42374a105-0+deb13u1		DSA-6424-1
xen	source	(unstable)	4.20.3+127-gc42374a105-1

[bullseye] - xen <end-of-life> (out of LTS support)
https://xenbits.xen.org/xsa/advisory-503.html