Answer in brief
CVE-2026-98717 records a Unknown severity vulnerability in KVM: x86/mmu: Bail from shadow walks if the root is invalid or a dummy. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=0e3223d8d00ac05849661f1b8b476d3caca251cf <e1bcabc07efd029ab414894127411129ffdb8b48 || >=0e3223d8d00ac05849661f1b8b476d3caca251cf <97c1dcce17ef27853860c781f9912257e6adbf7c || >=0e3223d8d00ac05849661f1b8b476d3caca251cf <681e31f03ec9219099a66a0f6e1bc48e1b5aa914 || >=0e3223d8d00ac05849661f1b8b476d3caca251cf <b6249c1d5665098c8bf12f8d3e4712bf04c775bc | e1bcabc07efd029ab414894127411129ffdb8b48, 97c1dcce17ef27853860c781f9912257e6adbf7c, 681e31f03ec9219099a66a0f6e1bc48e1b5aa914, b6249c1d5665098c8bf12f8d3e4712bf04c775bc |
| Linux/Linuxgeneric | 6.6 | Not reported |
| Linux/Linuxgeneric | >=0e3223d8d00ac05849661f1b8b476d3caca251cf <951fce1510645ba5df38da6fb85ece5726ec347d || >=0e3223d8d00ac05849661f1b8b476d3caca251cf <e1bcabc07efd029ab414894127411129ffdb8b48 || >=0e3223d8d00ac05849661f1b8b476d3caca251cf <97c1dcce17ef27853860c781f9912257e6adbf7c || >=0e3223d8d00ac05849661f1b8b476d3caca251cf <681e31f03ec9219099a66a0f6e1bc48e1b5aa914 || >=0e3223d8d00ac05849661f1b8b476d3caca251cf <b6249c1d5665098c8bf12f8d3e4712bf04c775bc | 951fce1510645ba5df38da6fb85ece5726ec347d, e1bcabc07efd029ab414894127411129ffdb8b48, 97c1dcce17ef27853860c781f9912257e6adbf7c, 681e31f03ec9219099a66a0f6e1bc48e1b5aa914, b6249c1d5665098c8bf12f8d3e4712bf04c775bc |
Published upstream
Oct 18, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 21, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 18, 2026
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: <TASK> 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/required to pre-check for a valid root. Don't WARN in the dummy root case as the whole point of using a dummy root is to provide a root that's valid enough to enter the guest, i.e. it should Just Work for all flows except those that *need* to know about dummy roots. Alternatively, KVM could allocate a dedicated page and associated shadow page structure for the dummy root, which is very tempting as it such an approach should be more resilient against unexpected behavior. But that would be a much larger and thus riskier change than simply terminating walks of dummy roots.
Quoted source text, attributed separately from HOL analysis.