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CVE PROGRAM SOURCE RECORD8.1 High

CVE-2026-23401

KVM: x86/mmu: Drop/zap existing present SPTE even when creating an MMIO SPTE

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86/mmu: Drop/zap existing present SPTE even when creating an MMIO SPTE When installing an emulated MMIO SPTE, do so *after* dropping/zapping the existing SPTE (if it's shadow-present). While commit a54aa15c6bda3 was right about it being impossible to convert a shadow-present SPTE to an MMIO SPTE due to a _guest_ write, it failed to account for writes to guest memory that are outside the scope of KVM. E.g. if host userspace modifies a shadowed gPTE to switch from a memslot to emulted MMIO and then the guest hits a relevant page fault, KVM will install the MMIO SPTE without first zapping the shadow-present SPTE. ------------[ cut here ]------------ is_shadow_present_pte(*sptep) WARNING: arch/x86/kvm/mmu/mmu.c:484 at mark_mmio_spte+0xb2/0xc0 [kvm], CPU#0: vmx_ept_stale_r/4292 Modules linked in: kvm_intel kvm irqbypass CPU: 0 UID: 1000 PID: 4292 Comm: vmx_ept_stale_r Not tainted 7.0.0-rc2-eafebd2d2ab0-sink-vm #319 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:mark_mmio_spte+0xb2/0xc0 [kvm] Call Trace: <TASK> mmu_set_spte+0x237/0x440 [kvm] ept_page_fault+0x535/0x7f0 [kvm] kvm_mmu_do_page_fault+0xee/0x1f0 [kvm] kvm_mmu_page_fault+0x8d/0x620 [kvm] vmx_handle_exit+0x18c/0x5a0 [kvm_intel] kvm_arch_vcpu_ioctl_run+0xc55/0x1c20 [kvm] kvm_vcpu_ioctl+0x2d5/0x980 [kvm] __x64_sys_ioctl+0x8a/0xd0 do_syscall_64+0xb5/0x730 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x47fa3f </TASK> ---[ end trace 0000000000000000 ]---

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • a54aa15c6bda3ca7e2f9e040ba968a1da303e24f to < 20656cd1f243d3a154aac5dd1b823110b6906fe1affected
  • a54aa15c6bda3ca7e2f9e040ba968a1da303e24f to < ed5909992f344a7d3f4024261e9f751d9618a27daffected
  • a54aa15c6bda3ca7e2f9e040ba968a1da303e24f to < fd28c5618699180cd69619801e9ae6a5266c0a22affected
  • a54aa15c6bda3ca7e2f9e040ba968a1da303e24f to < 459158151a158a6703b49f3c9de0e536d8bd553faffected
  • a54aa15c6bda3ca7e2f9e040ba968a1da303e24f to < 695320de6eadb75aaed8be1787c4ce4c189e4c7baffected
  • a54aa15c6bda3ca7e2f9e040ba968a1da303e24f to < bce7fe59d43531623f3e43779127bfb33804925daffected
  • a54aa15c6bda3ca7e2f9e040ba968a1da303e24f to < aad885e774966e97b675dfe928da164214a71605affected

Linux Linux

Default version status: affected

  • 5.13affected
  • 0 to < 5.13unaffected
  • 5.15.203 to ≤ 5.15.*unaffected
  • 6.1.168 to ≤ 6.1.*unaffected
  • 6.6.131 to ≤ 6.6.*unaffected
  • 6.12.80 to ≤ 6.12.*unaffected
  • 6.18.21 to ≤ 6.18.*unaffected
  • 6.19.11 to ≤ 6.19.*unaffected
  • 7.0 to ≤ *unaffected

References