Description
In the Linux kernel, the following vulnerability has been resolved:
xen/privcmd: restrict usage in unprivileged domU
The Xen privcmd driver allows to issue arbitrary hypercalls from
user space processes. This is normally no problem, as access is
usually limited to root and the hypervisor will deny any hypercalls
affecting other domains.
In case the guest is booted using secure boot, however, the privcmd
driver would be enabling a root user process to modify e.g. kernel
memory contents, thus breaking the secure boot feature.
The only known case where an unprivileged domU is really needing to
use the privcmd driver is the case when it is acting as the device
model for another guest. In this case all hypercalls issued via the
privcmd driver will target that other guest.
Fortunately the privcmd driver can already be locked down to allow
only hypercalls targeting a specific domain, but this mode can be
activated from user land only today.
The target domain can be obtained from Xenstore, so when not running
in dom0 restrict the privcmd driver to that target domain from the
beginning, resolving the potential problem of breaking secure boot.
This is XSA-482
---
V2:
- defer reading from Xenstore if Xenstore isn't ready yet (Jan Beulich)
- wait in open() if target domain isn't known yet
- issue message in case no target domain found (Jan Beulich)
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 2.6.37 | 5.10.253 |
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 | linux | 6.19.10-1 | — |
| Debian 13 | linux | 6.12.85-1 | — |
| Debian 12 | linux | 6.1.170-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | 6.8.0-1028.33 | — |
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | 5.15.0-1096.98 | — |
| Ubuntu 25.10 | linux +8 | No fix yet | — |
| Ubuntu 24.04 LTS | linux | 6.8.0-136.136 | USN-8567-1 |
| Ubuntu 24.04 LTS | linux-aws | 6.8.0-1061.64 | USN-8595-2 |
| Ubuntu 24.04 LTS | linux-azure | 6.8.0-1063.71 | USN-8606-1 |
| Ubuntu 24.04 LTS | linux-azure-fde | 6.8.0-1062.69 | USN-8607-1 |
| Ubuntu 24.04 LTS | linux-gcp | 6.8.0-1064.72 | USN-8567-1 |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1059.67 | USN-8567-1 |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1046.50 | USN-8567-1 |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1061.62 | USN-8574-3 |
| Ubuntu 24.04 LTS | linux-lowlatency | 6.8.0-136.136.2 | USN-8574-2 |
| Ubuntu 24.04 LTS | linux-nvidia | 6.8.0-1059.62 | USN-8596-1 |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1059.62.1 | USN-8596-1 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1030.31 | USN-8574-3 |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1058.61 | USN-8574-2 |
| Ubuntu 24.04 LTS | linux-raspi | 6.8.0-1061.65 | USN-8665-1 |
| Ubuntu 24.04 LTS | linux-riscv +27 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-vmware | 6.8.0-1008.8 | — |
| Ubuntu 24.04 LTS | linux-xilinx | 6.8.0-1033.34 | USN-8574-3 |
| Ubuntu 22.04 LTS | linux | 5.15.0-186.196 | USN-8575-1 |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1112.119 | USN-8575-2 |
| Ubuntu 22.04 LTS | linux-aws-6.8 | 6.8.0-1061.64~22.04.1 | USN-8595-3 |
| Ubuntu 22.04 LTS | linux-azure +1 | 5.15.0-1117.126 | USN-8610-1, USN-8575-3 |
| Ubuntu 22.04 LTS | linux-azure-6.8 | 6.8.0-1063.71~22.04.1 | USN-8606-1 |
| Ubuntu 22.04 LTS | linux-azure-fde-6.8 | 6.8.0-1062.69~22.04.1 | USN-8609-1 |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1112.122 | USN-8575-1 |
| Ubuntu 22.04 LTS | linux-gcp-6.8 | 6.8.0-1064.72~22.04.1 | USN-8567-1 |
| Ubuntu 22.04 LTS | linux-gke | 5.15.0-1108.114 | USN-8575-1 |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1095.103 | USN-8575-1 |
| Ubuntu 22.04 LTS | linux-hwe-6.8 | 6.8.0-136.136~22.04.1 | USN-8619-1 |
| Ubuntu 22.04 LTS | linux-ibm | 5.15.0-1106.110 | USN-8575-2 |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1061.62~22.04.1 | USN-8574-3 |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1107.113 | USN-8620-4 |
| Ubuntu 22.04 LTS | linux-kvm | 5.15.0-1104.109 | USN-8575-1 |
| Ubuntu 22.04 LTS | linux-lowlatency | 5.15.0-184.194 | USN-8575-1 |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.8 | 6.8.0-136.136.2~22.04.1 | USN-8574-2 |
| Ubuntu 22.04 LTS | linux-nvidia | 5.15.0-1107.108 | USN-8575-2 |
| Ubuntu 22.04 LTS | linux-nvidia-6.8 | 6.8.0-1059.62~22.04.1 | USN-8596-1 |
| Ubuntu 22.04 LTS | linux-nvidia-tegra | 5.15.0-1064.66 | USN-8576-2 |
| Ubuntu 22.04 LTS | linux-nvidia-tegra-igx | 5.15.0-1053.53 | USN-8576-2 |
| Ubuntu 22.04 LTS | linux-oracle | 5.15.0-1109.115 | USN-8575-3 |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1058.61~22.04.1 | USN-8595-1 |
| Ubuntu 22.04 LTS | linux-raspi | 5.15.0-1106.109 | USN-8668-2 |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv-6.8 | 6.8.0-136.136~22.04.3 | — |
| Ubuntu 22.04 LTS | linux-xilinx-zynqmp | 5.15.0-1075.79 | USN-8575-1 |
Show 18 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-raspi-realtime | 6.8.0-2050.52 | USN-8665-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime | 6.8.1-1056.57 | USN-8567-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.14 +1 | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1104.106 | USN-8620-3 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1111.120 | USN-8575-1 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1056.57~22.04.2 | USN-8567-1 |
| Ubuntu Pro FIPS 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS 16.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-aws-fips | 6.8.0-1061.64+fips1 | USN-8595-3 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-azure-fips | 6.8.0-1063.71+fips2 | USN-8608-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | 6.8.0-136.136+fips2 | USN-8574-2 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-gcp-fips | 6.8.0-1064.72+fips1 | USN-8574-1 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-aws-fips | 5.15.0-1112.119+fips1 | USN-8575-2 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-azure-fips | 5.15.0-1117.126+fips1 | USN-8620-2 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips | 5.15.0-186.196+fips1 | USN-8575-2 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-gcp-fips | 5.15.0-1112.122+fips1 | USN-8575-1 |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 16.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux +10 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux-aws-5.15 | 5.15.0-1112.119~20.04.1 | USN-8575-2 |
| Ubuntu Pro 20.04 LTS | linux-azure-5.15 | 5.15.0-1117.126~20.04.1 | USN-8620-1 |
| Ubuntu Pro 20.04 LTS | linux-azure-fde-5.15 | 5.15.0-1117.126~20.04.2 | USN-8620-1 |
| Ubuntu Pro 20.04 LTS | linux-gcp-5.15 | 5.15.0-1112.122~20.04.1 | USN-8668-1 |
| Ubuntu Pro 20.04 LTS | linux-hwe-5.15 | 5.15.0-186.196~20.04.1 | USN-8575-1 |
| Ubuntu Pro 20.04 LTS | linux-ibm-5.15 +1 | 5.15.0-1106.110~20.04.1 | — |
| Ubuntu Pro 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1107.113~20.04.1 | USN-8620-3 |
| Ubuntu Pro 20.04 LTS | linux-lowlatency-hwe-5.15 | 5.15.0-184.194~20.04.1 | USN-8575-1 |
| Ubuntu Pro 20.04 LTS | linux-nvidia-tegra-5.15 | 5.15.0-1064.66~20.04.1 | USN-8576-1 |
| Ubuntu Pro 20.04 LTS | linux-oracle-5.15 | 5.15.0-1109.115~20.04.1 | USN-8620-1 |
| Ubuntu Pro 18.04 LTS | linux +12 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | linux +7 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | linux +3 | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Micro 6.2 | gdk-pixbuf | 2.42.12-160000.4.1 | SUSE-SU-2026:21230-1 |
| SLE Micro 6.2 | kernel-default-base | 6.12.0-160000.27.1.160000.2.8 | SUSE-SU-2026:21237-1 |
| SLE Micro 6.2 | kernel-rt +5 | 6.12.0-160000.28.1 | SUSE-SU-2026:21237-1, SUSE-SU-2026:21230-1 |
| SLE Micro 6.1 | kernel-default-base | 6.4.0-41.1.21.18 | SUSE-SU-2026:21114-1 |
| SLE Micro 6.1 | kernel-rt +4 | 6.4.0-41.1 | SUSE-SU-2026:21255-1, SUSE-SU-2026:21114-1 |
| SLE Micro 6.0 | kernel-default-base | 6.4.0-41.1.21.18 | SUSE-SU-2026:21123-1 |
| SLE Micro 6.0 | kernel-source +2 | 6.4.0-41.1 | SUSE-SU-2026:21123-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7-RT_Update_11 | 1-150700.1.3.1 | SUSE-SU-2026:1573-1 |
| SUSE Real Time Module 15 SP7 | kernel-rt +1 | 6.4.0-150700.7.37.2 | SUSE-SU-2026:1573-1 |
| SUSE Real Time Module 15 SP7 | kernel-syms-rt | 6.4.0-150700.7.37.1 | SUSE-SU-2026:1573-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | kernel-default-base | 6.12.0-160000.27.1.160000.2.8 | openSUSE-SU-2026:20572-1 |
| openSUSE Leap 16.0 | kernel-rt +11 | 6.12.0-160000.28.1 | openSUSE-SU-2026:20572-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.18.20-20.229 +2 | 1:1.0-0.amzn2023 | ALAS2023-2026-1681, ALAS2023-2026-1596, ALAS2023-2026-1594 |
| Amazon Linux 2023 | perf +14 | 1:6.1.168-202.320.amzn2023 | ALAS2023-2026-1681 |
| Amazon Linux 2023 | perf6.12 +14 | 1:6.12.79-101.147.amzn2023 | ALAS2023-2026-1594 |
| Amazon Linux 2023 | perf6.18 +14 | 1:6.18.20-20.229.amzn2023 | ALAS2023-2026-1596 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-204.92.4.2.el10uek | ELSA-2026-50372 |
Advisories 38
- USN-8574-2 linux-fips, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-oracle vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8596-1 linux-nvidia, linux-nvidia-6.8, linux-nvidia-lowlatency vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8607-1 linux-azure-fde vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8608-1 linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8595-1 linux-oracle-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8595-3 linux-aws-6.8, linux-aws-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8609-1 linux-azure-fde-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8595-2 linux-aws vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8574-1 linux-gcp-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8574-3 linux-ibm, linux-ibm-6.8, linux-nvidia-tegra, linux-xilinx vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8619-1 linux-hwe-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8665-1 linux-raspi, linux-raspi-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8606-1 linux-azure, linux-azure-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8575-1 linux, linux-gcp, linux-gcp-fips, linux-gke, linux-gkeop, linux-hwe-5.15, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-realtime, linux-xilinx-zynqmp vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8575-2 linux-aws, linux-aws-5.15, linux-aws-fips, linux-fips, linux-ibm, linux-nvidia vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8620-1 linux-azure-5.15, linux-azure-fde-5.15, linux-oracle-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8620-3 linux-intel-iot-realtime, linux-intel-iotg-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8668-2 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8610-1 linux-azure-fde vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8575-3 linux-azure, linux-oracle vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8668-1 linux-gcp-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8576-1 linux-nvidia-tegra-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8576-2 linux-nvidia-tegra, linux-nvidia-tegra-igx vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8620-4 linux-intel-iotg vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8620-2 linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8567-1 linux, linux-gcp, linux-gcp-6.8, linux-gke, linux-gkeop, linux-realtime, linux-realtime-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 7, 2026
- ALAS2023-2026-1681 Important: kernel security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Aug 29, 2026
- SUSE-SU-2026:21230-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Jul 9, 2026
- WID-SEC-2026-0855 Xen: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Jul 6, 2026
- ELSA-2026-50372 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jul 2, 2026
- ALAS2023-2026-1594 Important: kernel6.12 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Jun 16, 2026
- ALAS2023-2026-1596 Important: kernel6.18 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Jun 16, 2026
- SUSE-SU-2026:21255-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Apr 24, 2026
- SUSE-SU-2026:1573-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Apr 24, 2026
- SUSE-SU-2026:21237-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Apr 23, 2026
- openSUSE-SU-2026:20572-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Apr 22, 2026
- SUSE-SU-2026:21123-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Apr 18, 2026
- SUSE-SU-2026:21114-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Apr 18, 2026
References
- https://git.kernel.org/stable/c/4eb245ff0d33b618e097a2c23de5df56d4ad6969
- https://git.kernel.org/stable/c/3ee5b9e3de4b8bdd74183d83205481c91a9effc8
- https://git.kernel.org/stable/c/87a803edb2ded911cb587c53bff179d2a2ed2a28
- https://git.kernel.org/stable/c/1879319d790f7d57622cdc22807b60ea78b56b6d
- https://git.kernel.org/stable/c/78432d8f0372c71c518096395537fa12be7ff24e
- https://git.kernel.org/stable/c/389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4
- https://git.kernel.org/stable/c/cbede2e833da1893afbea9b3ff29b5dda23a4a91
- https://git.kernel.org/stable/c/453b8fb68f3641fea970db88b7d9a153ed2a37e8