CVE-2026-23553

lowpriority · track · 0EPSS 0.001 · 4 %ileDEEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.14% (4th) EPSS

CVSS 2.9 · low

Is it mine?

7 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · cert_bund · nvd

EPSS · scored 2026-10-27

In the context switch logic Xen attempts to skip an IBPB in the case of a vCPU returning to a CPU on which it was the previous vCPU to run. While safe for Xen's isolation between vCPUs, this prevents the guest kernel correctly isolating between tasks. Consider: 1) vCPU runs on CPU A, running task 1. 2) vCPU moves to CPU B, idle gets scheduled on A. Xen skips IBPB. 3) On CPU B, guest kernel switches from task 1 to 2, issuing IBPB. 4) vCPU moves back to CPU A. Xen skips IBPB again. Now, task 2 is running on CPU A with task 1's training still in the BTB.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

Fixedxen-libs-0:4.14.6_28-150300.3.94.1.x86_64 as component of SUSE Linux Enterprise Micro 5.2suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.17.6_04-150500.3.59.1.x86_64 as component of SUSE Linux Enterprise Micro 5.5suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-0:4.18.5_10-150600.3.37.1.aarch64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-0:4.18.5_10-150600.3.37.1.x86_64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-devel-0:4.18.5_10-150600.3.37.1.aarch64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-devel-0:4.18.5_10-150600.3.37.1.x86_64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-doc-html-0:4.18.5_10-150600.3.37.1.aarch64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-doc-html-0:4.18.5_10-150600.3.37.1.x86_64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.18.5_10-150600.3.37.1.aarch64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.18.5_10-150600.3.37.1.x86_64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-32bit-0:4.18.5_10-150600.3.37.1.x86_64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-0:4.18.5_10-150600.3.37.1.aarch64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-0:4.18.5_10-150600.3.37.1.x86_64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-domU-0:4.18.5_10-150600.3.37.1.aarch64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-domU-0:4.18.5_10-150600.3.37.1.x86_64 as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-xendomains-wait-disk-0:4.18.5_10-150600.3.37.1.noarch as component of openSUSE Leap 15.6suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-0:4.12.4_64-3.137.1.x86_64 as component of SUSE Linux Enterprise Server LTSS Extended Security 12 SP5suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-devel-0:4.12.4_64-3.137.1.x86_64 as component of SUSE Linux Enterprise Server LTSS Extended Security 12 SP5suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-doc-html-0:4.12.4_64-3.137.1.x86_64 as component of SUSE Linux Enterprise Server LTSS Extended Security 12 SP5suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.12.4_64-3.137.1.x86_64 as component of SUSE Linux Enterprise Server LTSS Extended Security 12 SP5suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-32bit-0:4.12.4_64-3.137.1.x86_64 as component of SUSE Linux Enterprise Server LTSS Extended Security 12 SP5suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-0:4.12.4_64-3.137.1.x86_64 as component of SUSE Linux Enterprise Server LTSS Extended Security 12 SP5suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-domU-0:4.12.4_64-3.137.1.x86_64 as component of SUSE Linux Enterprise Server LTSS Extended Security 12 SP5suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-0:4.20.2_04-150700.3.22.1.x86_64 as component of SUSE Linux Enterprise Module for Server Applications 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-devel-0:4.20.2_04-150700.3.22.1.x86_64 as component of SUSE Linux Enterprise Module for Server Applications 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.20.2_04-150700.3.22.1.x86_64 as component of SUSE Linux Enterprise Module for Basesystem 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-0:4.20.2_04-150700.3.22.1.x86_64 as component of SUSE Linux Enterprise Module for Server Applications 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-domU-0:4.20.2_04-150700.3.22.1.x86_64 as component of SUSE Linux Enterprise Module for Basesystem 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-xendomains-wait-disk-0:4.20.2_04-150700.3.22.1.noarch as component of SUSE Linux Enterprise Module for Server Applications 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.16.7_06-150400.4.78.1.x86_64 as component of SUSE Linux Enterprise Micro 5.3suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.16.7_06-150400.4.78.1.x86_64 as component of SUSE Linux Enterprise Micro 5.4suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-0:4.20.2_06-150700.3.25.1.x86_64 as component of SUSE Linux Enterprise Module for Server Applications 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-devel-0:4.20.2_06-150700.3.25.1.x86_64 as component of SUSE Linux Enterprise Module for Server Applications 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.20.2_06-150700.3.25.1.x86_64 as component of SUSE Linux Enterprise Module for Basesystem 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-0:4.20.2_06-150700.3.25.1.x86_64 as component of SUSE Linux Enterprise Module for Server Applications 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-domU-0:4.20.2_06-150700.3.25.1.x86_64 as component of SUSE Linux Enterprise Module for Basesystem 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-xendomains-wait-disk-0:4.20.2_06-150700.3.25.1.noarch as component of SUSE Linux Enterprise Module for Server Applications 15 SP7suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-0:4.21.0_04-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-0:4.21.0_04-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-0:4.21.0_04-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-0:4.21.0_04-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-devel-0:4.21.0_04-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-devel-0:4.21.0_04-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-devel-0:4.21.0_04-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-devel-0:4.21.0_04-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-doc-html-0:4.21.0_04-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-doc-html-0:4.21.0_04-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-doc-html-0:4.21.0_04-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-doc-html-0:4.21.0_04-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.21.0_04-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.21.0_04-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.21.0_04-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-libs-0:4.21.0_04-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-0:4.21.0_04-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-0:4.21.0_04-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-0:4.21.0_04-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-0:4.21.0_04-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-domU-0:4.21.0_04-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-domU-0:4.21.0_04-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-domU-0:4.21.0_04-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-domU-0:4.21.0_04-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-xendomains-wait-disk-0:4.21.0_04-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-xendomains-wait-disk-0:4.21.0_04-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-xendomains-wait-disk-0:4.21.0_04-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedxen-tools-xendomains-wait-disk-0:4.21.0_04-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

cvss

Technical severity, 0–10. One row per scoring source.

5.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 2.7–5.5

v3.12.9lowCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:Nsecondary · ENISA EU

v3.12.9lowCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:Nsecondaryexploitability 1.4 · impact 1.4

v3.12.7lowCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)

v3.15.5mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Nsecondary · SUSE Product Security

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-665USCWE-693US

affected products (7)

Products and version ranges known to be affected.

Citrix Systems XenServer 8.4all versionscert_bundDEcpe:/a:citrix:xenserver:8.4
Debian Linuxall versionscert_bundDEcpe:/o:debian:debian_linux:-
Fedora Linuxall versionscert_bundDEcpe:/o:fedoraproject:fedora:-
SUSE Linuxall versionscert_bundDEcpe:/o:suse:suse_linux:-
SUSE openSUSEall versionscert_bundDEcpe:/o:suse:opensuse:-
Open Source Xen< 4.18.xcert_bundDE
xen xen≥ 4.6.0nvdUScpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*

advisories (9)

Vendor and ecosystem advisories describing this.

SUSE-SU-2026:0303-1Security update for xen2026-01-27csaf · suse_csafDE
Security update for xen
SUSE-SU-2026:0304-1Security update for xen2026-01-27csaf · suse_csafDE
Security update for xen
SUSE-SU-2026:0306-1Security update for xen2026-01-27csaf · suse_csafDE
Security update for xen
SUSE-SU-2026:0328-1Security update for xen2026-01-28csaf · suse_csafDE
Security update for xen
SUSE-SU-2026:0329-1Security update for xen2026-01-28csaf · suse_csafDE
Security update for xen
SUSE-SU-2026:0394-1Security update for xen2026-02-05csaf · suse_csafDE
Security update for xen
SUSE-SU-2026:0589-1Security update for xen2026-02-20csaf · suse_csafDE
Security update for xen
WID-SEC-W-2026-0229Citrix Systems XenServer und Xen: Schwachstelle ermöglicht Offenlegung von InformationenDeutsch2026-01-27csaf · cert_bundDE
Ein lokaler Angreifer kann eine Schwachstelle in Citrix Systems XenServer und Xen ausnutzen, um Informationen offenzulegen.
openSUSE-SU-2026:10118-1xen-4.21.0_04-1.1 on GA media2026-01-29csaf · suse_csafDE
xen-4.21.0_04-1.1 on GA media

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cert_bund nvd suse_csaf NVD CVE.org MITRE

published 2026-01-28modified 2026-06-17

references (10)

External citations — patches, advisories, analysis.

scry

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