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CVE-2026-98467: Linux

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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: arm64: nv: Fix null ptr deref on nested wp/unmap, teardown race Commit 7270cc9157f4 ("KVM: arm64: nv: Handle VNCR_EL2 invalidation from MMU notifiers") introduced VNCR_EL2 invalidation in both kvm_nested_s2_unmap() and kvm_nested_s2_wp(). However at the point of this being performed concurrent stage 2 teardown of a nested guest can cause kvm->arch.mmu.pgt to be set to NULL. This happens in kvm_flush_shadow_all() -> kvm_arch_flush_shadow_all() -> kvm_free_stage2_pgd() and is performed under the kvm->mmu_lock. Commit ec14c272408a ("KVM: arm64: nv: Unmap/flush shadow stage 2 page tables") introduced the teardown of the entire nested MMU range, which then invokes stage2_apply_range() with resched=true: mmu_notifier_invalidate_range_start() -> ... -> kvm_mmu_notifier_invalidate_range_start() -> kvm_mmu_unmap_gfn_range() -> kvm_unmap_gfn_range() -> kvm_nested_s2_unmap() -> kvm_stage2_unmap_range() -> __unmap_stage2_range() -> stage2_apply_range() This means that stage2_apply_range() can drop the kvm->mmu_lock and thus concurrent progress can be made in lockstep with kvm_arch_flush_shadow_all(). If kvm_arch_flush_shadow_all() advances ahead of stage2_apply_range() and completes its operation it guarantees a NULL pointer deref. Since kvm_free_stage2_pgd() is performed under the kvm->mmu_lock this will either be observed NULL or not and serialised against kvm_free_stage2_pgd(). Resolve the issue by abstracting the invalidation to a new function, kvm_invalidate_vncr_ipa_all(), and check that the pgt is non-NULL before dereferencing it.

    Засегнати продукти

    • Linux Linux: 7270cc9157f474dfc46750a34c9d7defc686b2eb преди 970de111c087488e53cadf5480b94e0f695db985; 7270cc9157f474dfc46750a34c9d7defc686b2eb преди 3cefc1ab511fad6a0f708e7a4aee9f91346e9457; 7270cc9157f474dfc46750a34c9d7defc686b2eb преди 4c74e233cdedd11592775fae2a6243e67ca3f891
    • Linux Linux: 6.16; преди 6.16; 6.18.55 до 6.18.*; 7.2.9 до 7.2.*; от 7.3 нататък

    История

    • 18 октомври 2026 Публикувано

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    Първоизточници

    CVE-2026-98467: Linux | freedomonline.bg