CVE-2025-40026: KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O

Q: What is the severity of CVE-2025-40026?

CVE-2025-40026 has a medium severity rating due to potential misuse of KVM in the Linux kernel.

Q: How do I fix CVE-2025-40026?

To fix CVE-2025-40026, update the Linux kernel to the latest patched version that addresses this vulnerability.

Q: Who is affected by CVE-2025-40026?

CVE-2025-40026 affects users running vulnerable versions of the Linux kernel that utilize KVM for virtualization.

Q: What systems are impacted by CVE-2025-40026?

Systems using the Linux kernel with KVM virtualization enabled are impacted by CVE-2025-40026.

Q: What kind of attack does CVE-2025-40026 allow?

CVE-2025-40026 can potentially allow an attacker to exploit userspace exits for I/O in a guest virtual machine.

Published Oct 28, 2025

Updated

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

KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O

When completing emulation of instruction that generated a userspace exit for I/O, don't recheck L1 intercepts as KVM has already finished that phase of instruction execution, i.e. has already committed to allowing L2 to perform I/O. If L1 (or host userspace) modifies the I/O permission bitmaps during the exit to userspace, KVM will treat the access as being intercepted despite already having emulated the I/O access.

Pivot on EMULTYPENODECODE to detect that KVM is completing emulation. Of the three users of EMULTYPENODECODE, only completeemulatedio() (the intended "recipient") can reach the code in question. gpinterception()'s use is mutually exclusive with isguestmode(), and completeemulatedinsngp() unconditionally pairs EMULTYPENODECODE with EMULTYPESKIP.

The bad behavior was detected by a syzkaller program that toggles port I/O interception during the userspace I/O exit, ultimately resulting in a WARN on vcpu->arch.pio.count being non-zero due to KVM no completing emulation of the I/O instruction.

WARNING: CPU: 23 PID: 1083 at arch/x86/kvm/x86.c:8039 emulatorpioinout+0x154/0x170 [kvm] Modules linked in: kvmintel kvm irqbypass CPU: 23 UID: 1000 PID: 1083 Comm: repro Not tainted 6.16.0-rc5-c1610d2d66b1-next-vm #74 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:emulatorpioinout+0x154/0x170 [kvm] PKRU: 55555554 Call Trace: <TASK> kvmfastpio+0xd6/0x1d0 [kvm] vmxhandleexit+0x149/0x610 [kvmintel] kvmarchvcpuioctlrun+0xda8/0x1ac0 [kvm] kvmvcpuioctl+0x244/0x8c0 [kvm] x64sysioctl+0x8a/0xd0 dosyscall64+0x5d/0xc60 entrySYSCALL64afterhwframe+0x4b/0x53 </TASK>

Other sources

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

KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O

The bad behavior was detected by a syzkaller program that toggles port I/O interception during the userspace I/O exit, ultimately resulting in a WARN on vcpu-arch.pio.count being non-zero due to KVM no completing emulation of the I/O instruction.

WARNING: CPU: 23 PID: 1083 at arch/x86/kvm/x86.c:8039 emulatorpioinout+0x154/0x170 [kvm] Modules linked in: kvmintel kvm irqbypass CPU: 23 UID: 1000 PID: 1083 Comm: repro Not tainted 6.16.0-rc5-c1610d2d66b1-next-vm #74 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:emulatorpioinout+0x154/0x170 [kvm] PKRU: 55555554 Call Trace: TASK kvmfastpio+0xd6/0x1d0 [kvm] vmxhandleexit+0x149/0x610 [kvmintel] kvmarchvcpuioctlrun+0xda8/0x1ac0 [kvm] kvmvcpuioctl+0x244/0x8c0 [kvm] x64sysioctl+0x8a/0xd0 dosyscall64+0x5d/0xc60 entrySYSCALL64afterhwframe+0x4b/0x53 /TASK

— IBM

Affected Software

237 affected componentsFixes available

Linux Linux kernel

Microsoft azl3 kernel 6.6.104.2-4

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-azure*

ubuntu/linux-lts-xenial*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-hwe*

ubuntu/linux-azure*

ubuntu/linux-gcp*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-kvm*

ubuntu/linux-oracle*

ubuntu/linux-fips*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-aws-5.4*

ubuntu/linux-azure*

ubuntu/linux-azure-4.15*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-5.4*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-4.15*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gcp-5.4*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-5.4*

ubuntu/linux-hwe-edge*

ubuntu/linux-ibm-5.4*

ubuntu/linux-kvm*

ubuntu/linux-oem*

ubuntu/linux-oracle*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-oracle-5.4*

ubuntu/linux-raspi-5.4*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.15<5.15.0-1100.107~20.04.2

5.15.0-1100.107~20.04.2

ubuntu/linux-aws-5.8*

ubuntu/linux-azure*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.15<5.15.0-1110.119~20.04.1

5.15.0-1110.119~20.04.1

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-bluefield*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.15<5.15.0-1100.109~20.04.1

5.15.0-1100.109~20.04.1

ubuntu/linux-gcp-5.8*

ubuntu/linux-gke*

ubuntu/linux-gke-5.15*

ubuntu/linux-gkeop*

ubuntu/linux-gkeop-5.15*

ubuntu/linux-hwe-5.11*

ubuntu/linux-hwe-5.13*

ubuntu/linux-hwe-5.15<5.15.0-170.180~20.04.3

5.15.0-170.180~20.04.3

ubuntu/linux-hwe-5.8*

ubuntu/linux-ibm*

ubuntu/linux-ibm-5.15<5.15.0-1094.97~20.04.1

5.15.0-1094.97~20.04.1

ubuntu/linux-intel-5.13*

ubuntu/linux-intel-iotg-5.15<5.15.0-1095.101~20.04.1

5.15.0-1095.101~20.04.1

ubuntu/linux-iot*

ubuntu/linux-kvm*

ubuntu/linux-lowlatency-hwe-5.15<5.15.0-170.180~20.04.1

5.15.0-170.180~20.04.1

ubuntu/linux-nvidia-tegra-5.15<5.15.0-1052.52~20.04.2

5.15.0-1052.52~20.04.2

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.15<5.15.0-1097.103~20.04.1

5.15.0-1097.103~20.04.1

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.15<5.15.0-1095.99~20.04.1

5.15.0-1095.99~20.04.1

ubuntu/linux-riscv-5.8*

ubuntu/linux-xilinx-zynqmp*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux<5.15.0-170.180

5.15.0-170.180

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws<5.15.0-1100.107

5.15.0-1100.107

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1050.53~22.04.1

6.8.0-1050.53~22.04.1

ubuntu/linux-azure<5.15.0-1109.118

5.15.0-1109.118

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1051.57~22.04.1

6.8.0-1051.57~22.04.1

ubuntu/linux-azure-fde<5.15.0-1109.118.1

5.15.0-1109.118.1

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8<6.8.0-1058.65~22.04.1

6.8.0-1058.65~22.04.1

ubuntu/linux-gcp<5.15.0-1100.109

5.15.0-1100.109

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1052.55~22.04.1

6.8.0-1052.55~22.04.1

ubuntu/linux-gke<5.15.0-1096.102

5.15.0-1096.102

ubuntu/linux-gkeop<5.15.0-1083.91

5.15.0-1083.91

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-hwe-6.8<6.8.0-106.106~22.04.1

6.8.0-106.106~22.04.1

ubuntu/linux-ibm<5.15.0-1094.97

5.15.0-1094.97

ubuntu/linux-ibm-6.8<6.8.0-1049.49~22.04.1

6.8.0-1049.49~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-intel-iotg<5.15.0-1095.101

5.15.0-1095.101

ubuntu/linux-kvm<5.15.0-1092.97

5.15.0-1092.97

ubuntu/linux-lowlatency<5.15.0-170.180

5.15.0-170.180

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-106.106.1~22.04.1

6.8.0-106.106.1~22.04.1

ubuntu/linux-nvidia<5.15.0-1095.96

5.15.0-1095.96

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8<6.8.0-1049.52~22.04.1

6.8.0-1049.52~22.04.1

ubuntu/linux-nvidia-tegra<5.15.0-1052.52

5.15.0-1052.52

ubuntu/linux-nvidia-tegra-igx<5.15.0-1041.41

5.15.0-1041.41

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle<5.15.0-1097.103

5.15.0-1097.103

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8<6.8.0-1047.48~22.04.1

6.8.0-1047.48~22.04.1

ubuntu/linux-raspi<5.15.0-1097.100

5.15.0-1097.100

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-106.106~22.04.1

6.8.0-106.106~22.04.1

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-xilinx-zynqmp<5.15.0-1064.68

5.15.0-1064.68

ubuntu/linux-bluefield<5.15.0-1084.86

5.15.0-1084.86

ubuntu/linux-intel-iot-realtime<5.15.0-1092.94

5.15.0-1092.94

ubuntu/linux-realtime<5.15.0-1099.108

5.15.0-1099.108

ubuntu/linux-realtime-6.8<6.8.1-1045.46~22.04.1

6.8.1-1045.46~22.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips<5.15.0-1100.107+fips1

5.15.0-1100.107+fips1

ubuntu/linux-azure-fips<5.15.0-1109.118+fips1

5.15.0-1109.118+fips1

ubuntu/linux-fips<5.15.0-170.180+fips1

5.15.0-170.180+fips1

ubuntu/linux-gcp-fips<5.15.0-1100.109+fips1

5.15.0-1100.109+fips1

ubuntu/linux<6.8.0-106.106

6.8.0-106.106

ubuntu/linux-aws<6.8.0-1050.53

6.8.0-1050.53

ubuntu/linux-aws-6.14*

ubuntu/linux-azure<6.8.0-1051.57

6.8.0-1051.57

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-fde<6.8.0-1058.65

6.8.0-1058.65

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-nvidia*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp<6.8.0-1052.55

6.8.0-1052.55

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gke<6.8.0-1048.53

6.8.0-1048.53

ubuntu/linux-gkeop<6.8.0-1035.38

6.8.0-1035.38

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-ibm<6.8.0-1049.49

6.8.0-1049.49

ubuntu/linux-lowlatency<6.8.0-106.106.1

6.8.0-106.106.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1049.52

6.8.0-1049.52

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-lowlatency<6.8.0-1049.52.1

6.8.0-1049.52.1

ubuntu/linux-nvidia-tegra<6.8.0-1020.20

6.8.0-1020.20

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.17<6.17.0-1006.6

6.17.0-1006.6

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1047.48

6.8.0-1047.48

ubuntu/linux-oracle-6.14*

ubuntu/linux-raspi<6.8.0-1050.54

6.8.0-1050.54

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14*

ubuntu/linux-xilinx<6.8.0-1028.29

6.8.0-1028.29

ubuntu/linux-bluefield<6.8.0-1017.21

6.8.0-1017.21

ubuntu/linux-raspi-realtime<6.8.0-2040.41

6.8.0-2040.41

ubuntu/linux-realtime<6.8.1-1045.46

6.8.1-1045.46

ubuntu/linux-realtime-6.14*

ubuntu/linux-aws-fips<6.8.0-1050.53+fips1

6.8.0-1050.53+fips1

ubuntu/linux-azure-fips<6.8.0-1052.58+fips1

6.8.0-1052.58+fips1

ubuntu/linux-fips<6.8.0-106.106+fips1

6.8.0-106.106+fips1

ubuntu/linux-gcp-fips<6.8.0-1052.55+fips1

6.8.0-1052.55+fips1

ubuntu/linux<6.17.0-7.7

6.17.0-7.7

ubuntu/linux-aws<6.17.0-1004.4

6.17.0-1004.4

ubuntu/linux-azure<6.17.0-1006.6

6.17.0-1006.6

ubuntu/linux-azure-fde*

ubuntu/linux-gcp<6.17.0-1004.4

6.17.0-1004.4

ubuntu/linux-oracle<6.17.0-1005.5

6.17.0-1005.5

ubuntu/linux-raspi<6.17.0-1005.5

6.17.0-1005.5

ubuntu/linux-realtime<6.17.0-1003.4

6.17.0-1003.4

ubuntu/linux-riscv<6.17.0-7.7.1

6.17.0-7.7.1

debian/linux

6.1.176-16.1.190-16.12.107-16.12.115-27.2.15-17.3.3-1

IBM Cloud Pak for Data System (Yosemite 1.0)<=11.3.1.2-IF1 - 11.3.1.2-IF2

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-aws-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1100.107~20.04.2
Upgrade
Upgrade ubuntu/linux-azure-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1110.119~20.04.1
Upgrade
Upgrade ubuntu/linux-gcp-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1100.109~20.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-170.180~20.04.3
Upgrade
Upgrade ubuntu/linux-ibm-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1094.97~20.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1095.101~20.04.1
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Upgrade ubuntu/linux-lowlatency-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-170.180~20.04.1
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Upgrade ubuntu/linux-nvidia-tegra-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1052.52~20.04.2
Upgrade
Upgrade ubuntu/linux-oracle-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1097.103~20.04.1
Upgrade
Upgrade ubuntu/linux-riscv-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1095.99~20.04.1
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Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.15.0-170.180
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.15.0-1100.107
Upgrade
Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1050.53~22.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.15.0-1109.118
Upgrade
Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1051.57~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 5.15.0-1109.118.1
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Upgrade ubuntu/linux-azure-fde-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1058.65~22.04.1
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Fixed in 5.15.0-1100.109
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Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1052.55~22.04.1
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Fixed in 5.15.0-1096.102
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Fixed in 5.15.0-1083.91
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Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-106.106~22.04.1
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Fixed in 5.15.0-1094.97
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Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1049.49~22.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg to a version that resolves this vulnerability.
Fixed in 5.15.0-1095.101
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Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 5.15.0-1092.97
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Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 5.15.0-170.180
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Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-106.106.1~22.04.1
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Fixed in 5.15.0-1095.96
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Fixed in 6.8.0-1049.52~22.04.1
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Fixed in 5.15.0-1052.52
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Upgrade ubuntu/linux-nvidia-tegra-igx to a version that resolves this vulnerability.
Fixed in 5.15.0-1041.41
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Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 5.15.0-1097.103
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Fixed in 6.8.0-1047.48~22.04.1
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Fixed in 5.15.0-1097.100
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Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-106.106~22.04.1
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Fixed in 5.15.0-1064.68
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Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 5.15.0-1084.86
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Upgrade ubuntu/linux-intel-iot-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1092.94
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Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1099.108
Upgrade
Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1045.46~22.04.1
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1100.107+fips1
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Fixed in 5.15.0-1109.118+fips1
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Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-170.180+fips1
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1100.109+fips1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 6.8.0-106.106
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.8.0-1050.53
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Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 6.8.0-1051.57
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Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 6.8.0-1058.65
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Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 6.8.0-1052.55
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Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 6.8.0-1048.53
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Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 6.8.0-1035.38
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Fixed in 6.8.0-1049.49
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Fixed in 6.8.0-106.106.1
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Fixed in 6.8.0-1049.52
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Fixed in 6.8.0-1049.52.1
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Fixed in 6.8.0-1020.20
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Fixed in 6.17.0-1006.6
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Fixed in 6.8.0-1047.48
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Fixed in 6.8.0-1050.54
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Fixed in 6.8.0-1028.29
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Fixed in 6.8.0-1017.21
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Fixed in 6.8.0-2040.41
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Fixed in 6.8.1-1045.46
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Fixed in 6.8.0-1050.53+fips1
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Fixed in 6.8.0-1052.58+fips1
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Fixed in 6.8.0-106.106+fips1
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Fixed in 6.8.0-1052.55+fips1
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Fixed in 6.17.0-7.7
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Fixed in 6.17.0-1004.4
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Fixed in 6.17.0-1006.6
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Fixed in 6.17.0-1004.4
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Fixed in 6.17.0-1005.5
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Fixed in 6.17.0-1005.5
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Fixed in 6.17.0-1003.4
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Fixed in 6.17.0-7.7.1
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Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.115-2Fixed in 7.2.15-1Fixed in 7.3.3-1

Event History

Oct 28, 2025

CVE Published

via MITRE·09:32 AM

Data Sourced

via MITRE·09:32 AM

DescriptionSeverity

Data Sourced

via Red Hat·10:01 AM

DescriptionSeverityAffected Software

Data Sourced

via OSV·10:15 AM

DescriptionSeverityAffected Software

Data Sourced

via NVD·10:15 AM

DescriptionSeverity

Oct 29, 2025

Data Sourced

via Microsoft·01:03 AM

DescriptionSeverityWeakness

Data Sourced

via Microsoft·01:03 AM

Affected Software

Oct 21, 2026

Data Sourced

via IBM·12:00 AM

DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

What is the severity of CVE-2025-40026?

CVE-2025-40026 has a medium severity rating due to potential misuse of KVM in the Linux kernel.

How do I fix CVE-2025-40026?

To fix CVE-2025-40026, update the Linux kernel to the latest patched version that addresses this vulnerability.

Who is affected by CVE-2025-40026?

CVE-2025-40026 affects users running vulnerable versions of the Linux kernel that utilize KVM for virtualization.

What systems are impacted by CVE-2025-40026?

Systems using the Linux kernel with KVM virtualization enabled are impacted by CVE-2025-40026.

What kind of attack does CVE-2025-40026 allow?

CVE-2025-40026 can potentially allow an attacker to exploit userspace exits for I/O in a guest virtual machine.

CVE-2025-40026: KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O

Other sources

Affected Software

Remediation

Event History

Parent advisories

Peer vulnerabilities

Frequently Asked Questions

What is the severity of CVE-2025-40026?

How do I fix CVE-2025-40026?

Who is affected by CVE-2025-40026?

What systems are impacted by CVE-2025-40026?

What kind of attack does CVE-2025-40026 allow?

Company

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