Reachable assertion in Xen - CVE-2026-23555

Vulnerability identifier: #VU124114

CSH Severity: Low

CVSS v4: 6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:H]

CVE-ID: CVE-2026-23555

CWE-ID: CWE-617

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to perform a denial of service attack.

The vulnerability exists due to improper input validation in xenstored when processing Xenstore commands with the node path of "/local/domain/". A local user can send a specially crafted request containing this illegal path to crash xenstored or force it into an infinite loop, resulting in a denial of service for Xenstore operations.

Exploitation does not require guest privileges beyond the ability to issue Xenstore commands. The vulnerability affects systems using the C variant of xenstored; systems using oxenstored or xenstore-stubdom are not affected.

Xen
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
Basesystem Module
Server Applications Module
openSUSE Leap
Fedora
xen-libs
xen-tools-xendomains-wait-disk
xen-libs-32bit-debuginfo
xen-libs-32bit
xen-tools
xen-libs-debuginfo
xen-tools-domU-debuginfo
xen-debugsource
xen-tools-debuginfo
xen-tools-domU
xen-devel
xen-doc-html
xen

Install updates from vendor's website.

xen-libs - addressed in versions 4.18.5_12-150600.3.40.1, 4.20.2_08-150700.3.28.1
xen-tools-xendomains-wait-disk - addressed in versions 4.18.5_12-150600.3.40.1, 4.20.2_08-150700.3.28.1
xen-libs-32bit-debuginfo - update to 4.18.5_12-150600.3.40.1
xen-libs-32bit - update to 4.18.5_12-150600.3.40.1
xen-tools - addressed in versions 4.18.5_12-150600.3.40.1, 4.20.2_08-150700.3.28.1
xen-libs-debuginfo - addressed in versions 4.18.5_12-150600.3.40.1, 4.20.2_08-150700.3.28.1
xen-tools-domU-debuginfo - addressed in versions 4.18.5_12-150600.3.40.1, 4.20.2_08-150700.3.28.1
xen-debugsource - addressed in versions 4.18.5_12-150600.3.40.1, 4.20.2_08-150700.3.28.1
xen-tools-debuginfo - addressed in versions 4.18.5_12-150600.3.40.1, 4.20.2_08-150700.3.28.1
xen-tools-domU - addressed in versions 4.18.5_12-150600.3.40.1, 4.20.2_08-150700.3.28.1
xen-devel - addressed in versions 4.18.5_12-150600.3.40.1, 4.20.2_08-150700.3.28.1
xen-doc-html - update to 4.18.5_12-150600.3.40.1
xen - addressed in versions 4.18.5_12-150600.3.40.1, 4.20.2_08-150700.3.28.1
xen - addressed in versions 4.19.5-1.fc42, 4.20.2-4.fc43, 4.21.0-5.fc44, 4.21.1-1.fc44

• https://xenbits.xen.org/xsa/advisory-481.html

• Multiple vulnerabilities in Xen
• Fedora 44 update for xen
• SUSE update for xen
• Fedora 43 update for xen
• Fedora 44 update for xen
• SUSE update for xen
• Fedora 42 update for xen