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KVM: x86/mmu: Bail from shadow walks if the root is invalid or a dummy

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: KVM: x86/mmu: Bail from shadow walks if the root is invalid or a dummy When walking shadow page tables, immediately terminate the walk if the root is a "dummy" root, i.e. a root whose top-level page table is backed by the zero page, but otherwise doesn't exist. If memslot creation races with a stage-2 page fault (EPT violation or #NPF) from L2, then if the stars align, KVM will attempt to walk shadow page tables using the zero page and hit a NULL pointer deref. BUG: kernel NULL pointer dereference, address: 0000000000000021 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP CPU: 30 UID: 1000 PID: 941 Comm: qemu Not tainted 7.2.0-rc2-1b731e5ded48-next-vm #1741 PREEMPTLAZY Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:__kvm_mmu_invalidate_addr+0xea/0x210 [kvm] Call Trace: kvm_mmu_invalidate_addr+0x92/0xe0 [kvm] __kvm_inject_emulated_page_fault+0x67/0x80 [kvm] ept_page_fault+0x160/0x850 [kvm] kvm_mmu_do_page_fault+0x102/0x1f0 [kvm] kvm_mmu_page_fault+0x8e/0x6b0 [kvm] vmx_handle_exit+0x163/0x640 [kvm_intel] kvm_arch_vcpu_ioctl_run+0x960/0x2120 [kvm] kvm_vcpu_ioctl+0x2c7/0x970 [kvm] __x64_sys_ioctl+0x90/0xd0 do_syscall_64+0x67/0x5f0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f606d0b53bb Opportunistically harden the shadow walks against fully invalid roots, but WARN, as all callers are expected/

Announced Source revision 1
Original source ↗

CVE-2026-98717

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-98717

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "0e3223d8d00ac05849661f1b8b476d3caca251cf",
        "lessThan": "951fce1510645ba5df38da6fb85ece5726ec347d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0e3223d8d00ac05849661f1b8b476d3caca251cf",
        "lessThan": "e1bcabc07efd029ab414894127411129ffdb8b48",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0e3223d8d00ac05849661f1b8b476d3caca251cf",
        "lessThan": "97c1dcce17ef27853860c781f9912257e6adbf7c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0e3223d8d00ac05849661f1b8b476d3caca251cf",
        "lessThan": "681e31f03ec9219099a66a0f6e1bc48e1b5aa914",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0e3223d8d00ac05849661f1b8b476d3caca251cf",
        "lessThan": "b6249c1d5665098c8bf12f8d3e4712bf04c775bc",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "arch/x86/kvm/mmu/mmu.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.6"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.6",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.113",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.56",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.10",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "arch/x86/kvm/mmu/mmu.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98717

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#48926 · Revision 1
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Publisher date
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