CVE-2026-23558

Name	CVE-2026-23558
Description	The adjustments made for XSA-379 as well as those subsequently becoming XSA-387 still left a race window, when a HVM or PVH guest does a grant table version change from v2 to v1 in parallel with mapping the status page(s) via XENMEM_add_to_physmap. Some of the status pages may then be freed while mappings of them would still be inserted into the guest's secondary (P2M) page tables.
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
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)	4.20.2+7-g1badcf5035-0+deb13u1	vulnerable
	forky, sid	4.20.2+37-g61ff35323e-1	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
xen	source	bullseye	(unfixed)	end-of-life
xen	source	(unstable)	(unfixed)

Notes

[trixie] - xen <no-dsa> (Minor issue)
[bookworm] - xen <no-dsa> (Minor issue)
[bullseye] - xen <end-of-life> (EOLed in Bullseye)
https://xenbits.xen.org/xsa/advisory-486.html