CVE-2026-23555

Name	CVE-2026-23555
Description	Any guest issuing a Xenstore command accessing a node using the (illegal) node path "/local/domain/", will crash xenstored due to a clobbered error indicator in xenstored when verifying the node path. Note that the crash is forced via a failing assert() statement in xenstored. In case xenstored is being built with NDEBUG #defined, an unprivileged guest trying to access the node path "/local/domain/" will result in it no longer being serviced by xenstored, other guests (including dom0) will still be serviced, but xenstored will use up all cpu time it can get.
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	fixed
	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
xen	source	bullseye	(unfixed)	end-of-life
xen	source	bookworm	(not affected)
xen	source	(unstable)	(unfixed)	unimportant

Notes

[bookworm] - xen <not-affected> (Vulnerable code not present)
[bullseye] - xen <end-of-life> (EOLed in Bullseye)
https://xenbits.xen.org/xsa/advisory-481.html
Debian uses the ocaml-based xenstored