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CVE-2026-98717: Linux

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CVSS

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Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

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    Описание

    Оригинално описание

    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

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    • Linux Linux: 0e3223d8d00ac05849661f1b8b476d3caca251cf преди 951fce1510645ba5df38da6fb85ece5726ec347d; 0e3223d8d00ac05849661f1b8b476d3caca251cf преди e1bcabc07efd029ab414894127411129ffdb8b48; 0e3223d8d00ac05849661f1b8b476d3caca251cf преди 97c1dcce17ef27853860c781f9912257e6adbf7c; 0e3223d8d00ac05849661f1b8b476d3caca251cf преди 681e31f03ec9219099a66a0f6e1bc48e1b5aa914; 0e3223d8d00ac05849661f1b8b476d3caca251cf преди b6249c1d5665098c8bf12f8d3e4712bf04c775bc
    • Linux Linux: 6.6; преди 6.6; 6.6.160 до 6.6.*; 6.12.113 до 6.12.*; 6.18.56 до 6.18.*; 7.2.10 до 7.2.*; от 7.3 нататък

    История

    • 18 октомври 2026 Публикувано

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