{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2026-98717",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-98717",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-10-18T15:46:51.862Z",
    "updatedAt": "2026-10-21T12:56:02.536Z",
    "importedAt": "2026-10-24T01:58:41.756Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "KVM: x86/mmu: Bail from shadow walks if the root is invalid or a dummy",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86/mmu: Bail from shadow walks if the root is invalid or a dummy\n\nWhen walking shadow page tables, immediately terminate the walk if the root\nis a \"dummy\" root, i.e. a root whose top-level page table is backed by the\nzero page, but otherwise doesn't exist.  If memslot creation races with a\nstage-2 page fault (EPT violation or #NPF) from L2, then if the stars align,\nKVM will attempt to walk shadow page tables using the zero page and hit a\nNULL pointer deref.\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000021\n  #PF: supervisor read access in kernel mode\n  #PF: error_code(0x0000) - not-present page\n  PGD 0 P4D 0\n  Oops: Oops: 0000 [#1] SMP\n  CPU: 30 UID: 1000 PID: 941 Comm: qemu Not tainted 7.2.0-rc2-1b731e5ded48-next-vm #1741 PREEMPTLAZY\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n  RIP: 0010:__kvm_mmu_invalidate_addr+0xea/0x210 [kvm]\n  Call Trace:\n   <TASK>\n   kvm_mmu_invalidate_addr+0x92/0xe0 [kvm]\n   __kvm_inject_emulated_page_fault+0x67/0x80 [kvm]\n   ept_page_fault+0x160/0x850 [kvm]\n   kvm_mmu_do_page_fault+0x102/0x1f0 [kvm]\n   kvm_mmu_page_fault+0x8e/0x6b0 [kvm]\n   vmx_handle_exit+0x163/0x640 [kvm_intel]\n   kvm_arch_vcpu_ioctl_run+0x960/0x2120 [kvm]\n   kvm_vcpu_ioctl+0x2c7/0x970 [kvm]\n   __x64_sys_ioctl+0x90/0xd0\n   do_syscall_64+0x67/0x5f0\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n  RIP: 0033:0x7f606d0b53bb\n\nOpportunistically harden the shadow walks against fully invalid roots, but\nWARN, as all callers are expected/required to pre-check for a valid root.\nDon't WARN in the dummy root case as the whole point of using a dummy root\nis to provide a root that's valid enough to enter the guest, i.e. it should\nJust Work for all flows except those that *need* to know about dummy roots.\n\nAlternatively, KVM could allocate a dedicated page and associated shadow\npage structure for the dummy root, which is very tempting as it such an\napproach should be more resilient against unexpected behavior.  But that\nwould be a much larger and thus riskier change than simply terminating\nwalks of dummy roots.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0e3223d8d00ac05849661f1b8b476d3caca251cf",
              "status": "affected",
              "versionType": "git",
              "lessThan": "951fce1510645ba5df38da6fb85ece5726ec347d"
            },
            {
              "version": "0e3223d8d00ac05849661f1b8b476d3caca251cf",
              "status": "affected",
              "versionType": "git",
              "lessThan": "e1bcabc07efd029ab414894127411129ffdb8b48"
            },
            {
              "version": "0e3223d8d00ac05849661f1b8b476d3caca251cf",
              "status": "affected",
              "versionType": "git",
              "lessThan": "97c1dcce17ef27853860c781f9912257e6adbf7c"
            },
            {
              "version": "0e3223d8d00ac05849661f1b8b476d3caca251cf",
              "status": "affected",
              "versionType": "git",
              "lessThan": "681e31f03ec9219099a66a0f6e1bc48e1b5aa914"
            },
            {
              "version": "0e3223d8d00ac05849661f1b8b476d3caca251cf",
              "status": "affected",
              "versionType": "git",
              "lessThan": "b6249c1d5665098c8bf12f8d3e4712bf04c775bc"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "6.6",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "6.6"
            },
            {
              "version": "6.6.160",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.113",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.18.56",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "version": "7.2.10",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "version": "7.3",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}