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Unscored CVE-2025-21779 EUVD-2025-5138GHSA-mmj4-6ppp-mqr2

KVM: x86: Reject Hyper-V's SEND_IPI hypercalls if local APIC isn't in-kernel

Published Feb 27, 2025 · Updated Nov 5, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: kernel Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.4 Package: linux-aws-5.8 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-fips Package: linux-azure Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.4 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.2 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.4 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.4 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-5.4 Package: linux-ibm-6.8 Package: linux-intel Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-iot Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.11 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.11 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.4 Package: linux-oracle-5.8 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-raspi Package: linux-raspi-5.4 Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86: Reject Hyper-V's SEND_IPI hypercalls if local APIC isn't in-kernel

Advertise support for Hyper-V's SEND_IPI and SEND_IPI_EX hypercalls if and
only if the local API is emulated/virtualized by KVM, and explicitly reject
said hypercalls if the local APIC is emulated in userspace, i.e. don't rely
on userspace to opt-in to KVM_CAP_HYPERV_ENFORCE_CPUID.

Rejecting SEND_IPI and SEND_IPI_EX fixes a NULL-pointer dereference if
Hyper-V enlightenments are exposed to the guest without an in-kernel local
APIC:

dump_stack+0xbe/0xfd
__kasan_report.cold+0x34/0x84
kasan_report+0x3a/0x50
__apic_accept_irq+0x3a/0x5c0
kvm_hv_send_ipi.isra.0+0x34e/0x820
kvm_hv_hypercall+0x8d9/0x9d0
kvm_emulate_hypercall+0x506/0x7e0
__vmx_handle_exit+0x283/0xb60
vmx_handle_exit+0x1d/0xd0
vcpu_enter_guest+0x16b0/0x24c0
vcpu_run+0xc0/0x550
kvm_arch_vcpu_ioctl_run+0x170/0x6d0
kvm_vcpu_ioctl+0x413/0xb20
__se_sys_ioctl+0x111/0x160
do_syscal1_64+0x30/0x40
entry_SYSCALL_64_after_hwframe+0x67/0xd1

Note, checking the sending vCPU is sufficient, as the per-VM irqchip_mode
can't be modified after vCPUs are created, i.e. if one vCPU has an
in-kernel local APIC, then all vCPUs have an in-kernel local APIC.

Affected products

VendorProductAffectedFixed
Linux Linux 4.20 5.10.236

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.

ReleasePackageFixed inAdvisory
Debian 14 linux 6.12.16-1 —
Debian 13 linux 6.12.16-1 —
Debian 12 linux 6.1.129-1 —
Debian 11 linux 5.10.237-1 DLA-4178-1
Debian 11 linux-6.1 6.1.129-1~deb11u1 DLA-4102-1
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1066.68 —
Ubuntu 24.04 LTS linux 6.8.0-78.78 USN-7703-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1035.37 USN-7703-1
Ubuntu 24.04 LTS linux-azure 6.8.0-1034.39 USN-7737-1
Ubuntu 24.04 LTS linux-azure-nvidia 6.8.0-1022.23 USN-7737-1
Ubuntu 24.04 LTS linux-gcp 6.8.0-1036.38 USN-7703-2
Ubuntu 24.04 LTS linux-gcp-6.11 +1 6.11.0-1015.15~24.04.1 USN-7521-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1032.36 USN-7703-4
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1019.21 USN-7703-2
Ubuntu 24.04 LTS linux-hwe-6.11 6.11.0-26.26~24.04.1 USN-7521-1
Ubuntu 24.04 LTS linux-ibm 6.8.0-1033.33 USN-7703-2
Ubuntu 24.04 LTS linux-intel +4 No fix yet —
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-78.78.1 USN-7703-1
Ubuntu 24.04 LTS linux-lowlatency-hwe-6.11 6.11.0-1014.15~24.04.1 USN-7521-3
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1035.38 USN-7703-4
Ubuntu 24.04 LTS linux-nvidia-6.11 6.11.0-1010.10 —
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1035.38.1 USN-7703-4
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1009.9 —
Ubuntu 24.04 LTS linux-oem-6.11 6.11.0-1022.22 USN-7521-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1032.33 USN-7703-3
Ubuntu 24.04 LTS linux-raspi 6.8.0-1035.39 USN-7703-4
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1017.18 —
Ubuntu 22.04 LTS linux +1 5.15.0-140.150 USN-7510-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1084.91 USN-7510-7
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1035.37~22.04.1 USN-7703-2
Ubuntu 22.04 LTS linux-azure 5.15.0-1089.98 USN-7510-3
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1034.39~22.04.1 USN-7737-1
Ubuntu 22.04 LTS linux-azure-fde 5.15.0-1089.98.1 —
Ubuntu 22.04 LTS linux-gcp 5.15.0-1083.92 USN-7511-1
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1036.38~22.04.1 USN-7703-2
Ubuntu 22.04 LTS linux-gke +1 5.15.0-1081.87 USN-7511-3, USN-7510-1
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1066.74 USN-7510-1
Ubuntu 22.04 LTS linux-hwe-6.8 +1 6.8.0-78.78~22.04.1 USN-7703-4
Ubuntu 22.04 LTS linux-ibm 5.15.0-1076.79 USN-7510-1
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1033.33~22.04.1 USN-7703-2
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1079.85 USN-7510-1
Ubuntu 22.04 LTS linux-kvm 5.15.0-1080.85 USN-7510-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-78.78.1~22.04.1 USN-7703-1
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1078.79 USN-7510-1
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1035.38~22.04.1 USN-7703-4
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1037.37 USN-7510-3
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1026.26 USN-7510-7
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1032.33~22.04.1 USN-7703-3
Ubuntu 22.04 LTS linux-raspi 5.15.0-1078.81 USN-7510-7
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1050.54 USN-7602-1
Ubuntu 20.04 LTS linux-aws-5.15 5.15.0-1084.91~20.04.1 USN-7510-8
Ubuntu 20.04 LTS linux-azure-5.15 5.15.0-1089.98~20.04.1 USN-7510-3
Ubuntu 20.04 LTS linux-gcp-5.15 5.15.0-1083.92~20.04.1 USN-7512-1
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Ubuntu 20.04 LTS linux-ibm-5.15 5.15.0-1076.79~20.04.1 USN-7510-1
Ubuntu 20.04 LTS linux-intel-iotg-5.15 5.15.0-1079.85~20.04.1 USN-7510-7
Ubuntu 20.04 LTS linux-lowlatency-hwe-5.15 5.15.0-140.150~20.04.1 USN-7510-1
Ubuntu 20.04 LTS linux-oracle-5.15 5.15.0-1081.87~20.04.1 USN-7510-1
Ubuntu 20.04 LTS linux-riscv-5.15 5.15.0-1079.83~20.04.1 —
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Show 10 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-raspi-realtime 6.8.0-2028.29 USN-7719-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1030.31 USN-7703-1
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1077.79 USN-7510-4
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1084.93 USN-7510-4
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1030.31~22.04.1 —
Ubuntu Pro FIPS 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-78.78+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1084.91+fips1 USN-7510-6
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1089.98+fips1 USN-7510-5
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-140.150+fips1 USN-7510-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1083.92+fips1 USN-7511-2
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips +3 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-hwe-5.15 5.15.0-142.152~20.04.1 USN-7593-1
Ubuntu Pro 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1039.39~20.04.1 —
Ubuntu Pro 18.04 LTS linux-aws-5.4 +6 No fix yet —
ReleasePackageFixed inAdvisory
SLES 15 SP6 kernel-64kb +3 6.4.0-150600.23.47.2 SUSE-SU-2025:1180-1
SLES 15 SP6 kernel-azure +1 6.4.0-150600.8.34.2 SUSE-SU-2025:1177-1
SLES 15 SP6 kernel-coco +3 6.4.0-15061.21.coco15sp6.1 SUSE-SU-2025:01919-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.47.2.150600.12.20.2 SUSE-SU-2025:1180-1
SLES 15 SP6 kernel-docs +2 6.4.0-150600.23.47.1 SUSE-SU-2025:1180-1
SLES 15 SP6 kernel-syms-azure 6.4.0-150600.8.34.1 SUSE-SU-2025:1177-1
SLES 12 SP5 kernel-syms +2 4.12.14-122.258.1 SUSE-SU-2025:01600-1
Show 5 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLE Micro 6.1 kernel-default-base 6.4.0-28.1.21.6 SUSE-SU-2025:20270-1
SLE Micro 6.1 kernel-livepatch-MICRO-6-0_Update_6 +1 1-3.1 SUSE-SU-2025:20270-1, SUSE-SU-2025:20260-1
SLE Micro 6.1 kernel-rt +4 6.4.0-28.1 SUSE-SU-2025:20270-1, SUSE-SU-2025:20260-1
SLE Micro 6.0 kernel-default-base 6.4.0-28.1.21.6 SUSE-SU-2025:20192-1
SLE Micro 6.0 kernel-livepatch-MICRO-6-0_Update_6 +1 1-3.1 SUSE-SU-2025:20192-1, SUSE-SU-2025:20190-1
SLE Micro 6.0 kernel-rt +4 6.4.0-28.1 SUSE-SU-2025:20192-1, SUSE-SU-2025:20190-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.47.2 SUSE-SU-2025:1180-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_10 1-150600.1.5.1 SUSE-SU-2025:1178-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_10 1-150600.13.5.1 SUSE-SU-2025:1180-1
SLE Live Patching 12 SP5 kernel-default 4.12.14-122.258.1 SUSE-SU-2025:01600-1
SLE Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_68 1-8.3.1 SUSE-SU-2025:01600-1
SUSE Real Time Module 15 SP6 kernel-rt +3 6.4.0-150600.10.34.1 SUSE-SU-2025:1178-1
ReleasePackageFixed inAdvisory
openSUSE Leap 15.6 dtb-aarch64 +4 6.4.0-150600.23.47.1 SUSE-SU-2025:1180-1
openSUSE Leap 15.6 kernel-64kb +5 6.4.0-150600.23.47.2 SUSE-SU-2025:1180-1
openSUSE Leap 15.6 kernel-azure +1 6.4.0-150600.8.34.2 SUSE-SU-2025:1177-1
openSUSE Leap 15.6 kernel-default-base 6.4.0-150600.23.47.2.150600.12.20.2 SUSE-SU-2025:1180-1
openSUSE Leap 15.6 kernel-rt +3 6.4.0-150600.10.34.1 SUSE-SU-2025:1178-1
openSUSE Leap 15.6 kernel-syms-azure 6.4.0-150600.8.34.1 SUSE-SU-2025:1177-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.1.129-138.220 1.0-0.amzn2023 ALAS2023-2025-876
Amazon Linux 2023 perf +14 6.1.129-138.220.amzn2023 ALAS2023-2025-876

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.79.1-1 —
Azure Linux 2 (CBL-Mariner) kernel 5.15.179.1-1 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 kernel-uek +34 6.12.0-101.33.4.3.el10uek ELSA-2025-20530, ELSA-2025-20480

Advisories 41

References