Description
Accesses to the CMOS memory contents are done using an indirect IO port
pair. Therefore Xen needs to cache the guest chosen index, and one of
the usages of the index didn't take the necessary locking to avoid
concurrent changes. As a result, a guest could change the index after
it being checked, causing a subsequent out-of-bound read access to the
contents of an array.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Xen | Xen | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | xen | 4.20.3+127-gc42374a105-1 | — |
| Debian 13 | xen | 4.20.3+127-gc42374a105-0+deb13u1 | — |
| Debian 12 | xen | 4.17.7-0+deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | xen | No fix yet | — |
| Ubuntu 26.04 LTS | xen | No fix yet | — |
| Ubuntu 24.04 LTS | xen | No fix yet | — |
| Ubuntu 22.04 LTS | xen | No fix yet | — |
| Ubuntu 20.04 LTS | xen | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | xen | No fix yet | — |
| Ubuntu 16.04 LTS | xen | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | xen | 4.20.4_04-150700.3.46.1 | SUSE-SU-2026:4090-1 |
| SLES 15 SP6 | xen | 4.18.5_20-150600.3.53.3 | SUSE-SU-2026:3409-1 |
| SLES 15 SP5 | xen | 4.17.6_14-150500.3.76.3 | SUSE-SU-2026:3423-1 |
| SLES 15 SP4 | xen | 4.16.7_12-150400.4.89.3 | SUSE-SU-2026:3462-1 |
| SLES 12 SP5 | xen | 4.12.4_72-3.148.4 | SUSE-SU-2026:3451-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP6 | xen | 4.18.5_20-150600.3.53.3 | SUSE-SU-2026:3409-1 |
| SLES for SAP 15 SP5 | xen | 4.17.6_14-150500.3.76.3 | SUSE-SU-2026:3423-1 |
| SLES for SAP 15 SP4 | xen | 4.16.7_12-150400.4.89.3 | SUSE-SU-2026:3462-1 |
| SLE Micro 5.5 | xen | 4.17.6_14-150500.3.76.3 | SUSE-SU-2026:3423-1 |
| SLE Micro 5.4 | xen | 4.16.7_12-150400.4.89.3 | SUSE-SU-2026:3462-1 |
| SLE Micro 5.3 | xen | 4.16.7_12-150400.4.89.3 | SUSE-SU-2026:3462-1 |
| SLE HPC 15 SP5 | xen | 4.17.6_14-150500.3.76.3 | SUSE-SU-2026:3423-1 |
| SLE HPC 15 SP4 | xen | 4.16.7_12-150400.4.89.3 | SUSE-SU-2026:3462-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | xen | 4.22.0_02-1.1 | openSUSE-SU-2026:11441-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | xen | 4.21.2-r0 | — |
| Alpine v3.23 | xen | 4.20.4-r0 | — |
| Alpine v3.22 | xen | 4.20.4-r0 | — |
| Alpine v3.21 | xen | 4.19.6-r0 | — |
Advisories 7
- WID-SEC-2026-2568 Xen: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 4, 2026
- SUSE-SU-2026:4090-1 Security update for xen SUSE / openSUSE Security Updates · Sep 13, 2026
- SUSE-SU-2026:3462-1 Security update for xen SUSE / openSUSE Security Updates · Aug 4, 2026
- SUSE-SU-2026:3451-1 Security update for xen SUSE / openSUSE Security Updates · Aug 4, 2026
- openSUSE-SU-2026:11441-1 xen-4.22.0_02-1.1 on GA media SUSE / openSUSE Security Updates · Aug 4, 2026
- SUSE-SU-2026:3409-1 Security update for xen SUSE / openSUSE Security Updates · Jul 30, 2026
- SUSE-SU-2026:3423-1 Security update for xen SUSE / openSUSE Security Updates · Jul 30, 2026