In the Linux kernel, the following vulnerability has been resolved:
KVM: nVMX: Reset MMU back to the root MMU if loading L2 state fails for !VM-Entry
Reset the vCPU's MMU pointer back to the root MMU if loading L2 state fails
in the "not from VM-Entry" case, i.e. when emulating RSM or handling
KVM_SET_NESTED_STATE. Failure to unwind the MMU pointer results in KVM
trying to run L1 with a nested MMU, and is especially problematic if the
vCPU manages to free its nested state before the VM crashes. Constructing
the root for a nested EPT MMU goes through vmcs12, which is dynamically
allocated/freed when nVMX is enabled/disabled. And so if the nested state
is freed with the MMU still pointing at the nested MMU, KVM will hit a NULL
pointer deref when attempting to get L1=>L2 EPTP.
BUG: kernel NULL pointer dereference, address: 0000000000000078
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 114a2d067 P4D 111743067 PUD 11141f067 PMD 0
Oops: Oops: 0000 [#1] SMP
CPU: 20 UID: 1000 PID: 1272 Comm: nested_tdp_faul Not tainted 7.3.0-rc4-8c89f11d1a99b-sink-vm #1914 PREEMPTLAZY
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:nested_ept_get_eptp+0xb/0x10 [kvm_intel]
Call Trace:
<TASK>
kvm_mmu_load+0xcd/0x870 [kvm]
kvm_arch_vcpu_ioctl_run+0x18f5/0x1f80 [kvm]
kvm_vcpu_ioctl+0x2c7/0x970 [kvm]
__x64_sys_ioctl+0x90/0xd0
do_syscall_64+0x9c/0x4d0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x47491b
</TASK>
Modules linked in: kvm_intel kvm irqbypass
CR2: 0000000000000078
---[ end trace 0000000000000000 ]---
RIP: 0010:nested_ept_get_eptp+0xb/0x10 [kvm_intel]
[sean: write changelog]
KVM: nVMX: Reset MMU back to the root MMU if loading L2 state fails for !VM-Entry
Reset the vCPU's MMU pointer back to the root MMU if loading L2 state fails
in the "not from VM-Entry" case, i.e. when emulating RSM or handling
KVM_SET_NESTED_STATE. Failure to unwind the MMU pointer results in KVM
trying to run L1 with a nested MMU, and is especially problematic if the
vCPU manages to free its nested state before the VM crashes. Constructing
the root for a nested EPT MMU goes through vmcs12, which is dynamically
allocated/freed when nVMX is enabled/disabled. And so if the nested state
is freed with the MMU still pointing at the nested MMU, KVM will hit a NULL
pointer deref when attempting to get L1=>L2 EPTP.
BUG: kernel NULL pointer dereference, address: 0000000000000078
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 114a2d067 P4D 111743067 PUD 11141f067 PMD 0
Oops: Oops: 0000 [#1] SMP
CPU: 20 UID: 1000 PID: 1272 Comm: nested_tdp_faul Not tainted 7.3.0-rc4-8c89f11d1a99b-sink-vm #1914 PREEMPTLAZY
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:nested_ept_get_eptp+0xb/0x10 [kvm_intel]
Call Trace:
<TASK>
kvm_mmu_load+0xcd/0x870 [kvm]
kvm_arch_vcpu_ioctl_run+0x18f5/0x1f80 [kvm]
kvm_vcpu_ioctl+0x2c7/0x970 [kvm]
__x64_sys_ioctl+0x90/0xd0
do_syscall_64+0x9c/0x4d0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x47491b
</TASK>
Modules linked in: kvm_intel kvm irqbypass
CR2: 0000000000000078
---[ end trace 0000000000000000 ]---
RIP: 0010:nested_ept_get_eptp+0xb/0x10 [kvm_intel]
[sean: write changelog]
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
||||||||||||||||||
| Linux | Linux | affected |
|
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Fixes
Solution
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Workaround
No workaround given by the vendor.
References
History
Wed, 28 Oct 2026 12:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-476 |
Wed, 28 Oct 2026 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: KVM: nVMX: Reset MMU back to the root MMU if loading L2 state fails for !VM-Entry Reset the vCPU's MMU pointer back to the root MMU if loading L2 state fails in the "not from VM-Entry" case, i.e. when emulating RSM or handling KVM_SET_NESTED_STATE. Failure to unwind the MMU pointer results in KVM trying to run L1 with a nested MMU, and is especially problematic if the vCPU manages to free its nested state before the VM crashes. Constructing the root for a nested EPT MMU goes through vmcs12, which is dynamically allocated/freed when nVMX is enabled/disabled. And so if the nested state is freed with the MMU still pointing at the nested MMU, KVM will hit a NULL pointer deref when attempting to get L1=>L2 EPTP. BUG: kernel NULL pointer dereference, address: 0000000000000078 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 114a2d067 P4D 111743067 PUD 11141f067 PMD 0 Oops: Oops: 0000 [#1] SMP CPU: 20 UID: 1000 PID: 1272 Comm: nested_tdp_faul Not tainted 7.3.0-rc4-8c89f11d1a99b-sink-vm #1914 PREEMPTLAZY Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:nested_ept_get_eptp+0xb/0x10 [kvm_intel] Call Trace: <TASK> kvm_mmu_load+0xcd/0x870 [kvm] kvm_arch_vcpu_ioctl_run+0x18f5/0x1f80 [kvm] kvm_vcpu_ioctl+0x2c7/0x970 [kvm] __x64_sys_ioctl+0x90/0xd0 do_syscall_64+0x9c/0x4d0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x47491b </TASK> Modules linked in: kvm_intel kvm irqbypass CR2: 0000000000000078 ---[ end trace 0000000000000000 ]--- RIP: 0010:nested_ept_get_eptp+0xb/0x10 [kvm_intel] [sean: write changelog] | |
| Title | KVM: nVMX: Reset MMU back to the root MMU if loading L2 state fails for !VM-Entry | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-28T10:35:30.615Z
Reserved: 2026-09-25T10:25:14.399Z
Link: CVE-2026-99176
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-28T11:17:38.270
Modified: 2026-10-28T11:17:38.270
Link: CVE-2026-99176
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-10-28T12:30:17Z
Weaknesses