CVE-2026-23557

Name	CVE-2026-23557
Description	Any guest can cause xenstored to crash by issuing a XS_RESET_WATCHES command within a transaction due to an assert() triggering. In case xenstored was built with NDEBUG #defined nothing bad will happen, as assert() is doing nothing in this case. Note that the default is not to define NDEBUG for xenstored builds even in release builds of Xen.
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	(unstable)	(unfixed)	unimportant

https://xenbits.xen.org/xsa/advisory-484.html
Debian uses the ocaml-based xenstored