CVE-2026-53359
摘要
In the Linux kernel, the following vulnerability has been resolved:KVM: x86: Fix shadow paging use-after-free due to unexpected roleCommit 0cb2af2ea66ad ("KVM: x86: Fix shadow paging use-after-free dueto unexpected GFN") fixed a shadow paging mismatch between stored andcomputed GFNs; the bug could be triggered by changing a PDE mapping fromoutside the guest, and then deleting a memslot. The rmap_remove()call would miss entries created after the PDE change because the GFNof the leaf SPTE does not match the GFN of the struct kvm_mmu_page.A similar hole however remains if the modified PDE points to a non-leafpage. In this case the gfn can be made to match, but the role does notmatch: the original large 2MB page creates a kvm_mmu_page with direct=1,while the new 4KB needs a kvm_mmu_page with direct=0. However,kvm_mmu_get_child_sp() does not compare the role, and therefore reusesthe page.The next step is installing a leaf (4KB) SPTE on the new path whichrecords an rmap entry under the gfn resolved by the walk. But whenthat child is zapped its parent kvm_mmu_page has direct=1 andkvm_mmu_page_get_gfn() computes the gfn for the 4KB page assp->gfn + index instead of using sp->shadowed_translation[] (or sp->gfns[]in older kernels). It therefore fails to remove the recorded entry.When the memslot is dropped the shadow page is freed but the rmapentry survives, as in the scenario that was already fixed. Code thatlater walks that gfn (dirty logging, MMU notifier invalidation, andso on) dereferences an sptep that lies in the freed page, causing theuse-after-free.
标签
- cve:cve-2026-53359
- type:cve
- vendor:alibaba
扩展字段
{
"cve_id": "CVE-2026-53359",
"raw_pub_date": "Fri, 24 Jul 2026 17:46:35 +0800"
}