{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-80726", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-80726" ], "published": "2026-09-03T08:22:05Z", "summary": "KVM: x86/mmu: WARN and clear role.invalid when creating a child shadow page", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86/mmu: WARN and clear role.invalid when creating a child shadow page\n\nExplicitly clear role.invalid when deriving a child shadow page's role from\nits parent to harden against bugs elsewhere in KVM, as violating KVM's\ninvariant that invalid pages are NOT on the list of active MMU pages leads\nto use-after-free due to __kvm_mmu_prepare_zap_page() using list_add()\ninstead of list_move() when processing an invalid shadow page, i.e. makes a\nbad situation far worse.\n\nYell loudly if the parent is invalid, as it means KVM has missed a validity\ncheck, i.e. KVM is attempting to map memory using an invalid/obsolete root,\nbut continue on as the child is otherwise still a valid shadow page.\n\n ==================================================================\n BUG: KASAN: slab-use-after-free in __kvm_mmu_get_shadow_page+0x1817/0x1860 [kvm]\n Write of size 8 at addr ff11000153dd1368 by task repro/853\n\n CPU: 1 UID: 1000 PID: 853 Comm: repro Not tainted 7.2.0-rc2-3aec122bdcaf-next-vm #5 PREEMPT\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n Call Trace:\n \n dump_stack_lvl+0x4b/0x70\n print_report+0x153/0x49c\n kasan_report+0xbc/0xf0\n __kvm_mmu_get_shadow_page+0x1817/0x1860 [kvm]\n mmu_alloc_root+0x141/0x320 [kvm]\n kvm_mmu_load+0x612/0x20f0 [kvm]\n kvm_arch_vcpu_ioctl_run+0x3dd5/0x6150 [kvm]\n kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]\n __x64_sys_ioctl+0x131/0x1b0\n do_syscall_64+0x67/0x5f0\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n \n\n Allocated by task 853:\n kasan_save_stack+0x20/0x40\n kasan_save_track+0x14/0x30\n __kasan_slab_alloc+0x5f/0x70\n kmem_cache_alloc_noprof+0xfe/0x2e0\n __kvm_mmu_topup_memory_cache+0x135/0x530 [kvm]\n paging64_page_fault+0x318/0x1e30 [kvm]\n kvm_mmu_do_page_fault+0x21d/0x630 [kvm]\n kvm_mmu_page_fault+0x18c/0x17b0 [kvm]\n kvm_arch_vcpu_ioctl_run+0x1f35/0x6150 [kvm]\n kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]\n __x64_sys_ioctl+0x131/0x1b0\n do_syscall_64+0x67/0x5f0\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n Freed by task 853:\n kasan_save_stack+0x20/0x40\n kasan_save_track+0x14/0x30\n kasan_save_free_info+0x3b/0x60\n __kasan_slab_free+0x43/0x70\n kmem_cache_free+0xe2/0x400\n kvm_mmu_commit_zap_page.part.0+0x1e2/0x310 [kvm]\n kvm_mmu_free_roots+0x283/0x560 [kvm]\n kvm_arch_vcpu_ioctl_run+0x33c8/0x6150 [kvm]\n kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]\n __x64_sys_ioctl+0x131/0x1b0\n do_syscall_64+0x67/0x5f0\n entry_SYSCALL_64_after_hwframe+0x4b/0x53", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.183", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-80726" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/ec4eb5c2ef964bf398f07889265121c316561911" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/9b7984692c18b22d6d61af3f53887fca7fddb0f1" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/f33ecb89d352348ed5e625f6747ac51ede254e1b" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/0af4711862c5b818204d40b21f0859ad51c230e9" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/66bc868a33cf1de43f22a94acd8857e0fe33393f" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/9f7760a2e962cbda0d096a27d394d14ad4d22928" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/5ec42d57655c690234c14aece6dd3f209778c1d8" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-10-03T11:04:09Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 9.3, "cvss_v3_severity": "Critical", "scenario": "AV:L - The bug is reached only through host KVM x86 shadow-MMU handling on the KVM_RUN ioctl path (kvm_arch_vcpu_ioctl_run -> kvm_mmu_page_fault/kvm_mmu_load -> __kvm_mmu_get_shadow_page), driven by guest page faults and root reloads, not by remote network or physical input.\nAC:L - The reproducer (UID 1000) triggers this reliably by combining guest page-table churn with MMU reclaim (make_mmu_pages_available/kvm_mmu_zap_oldest_mmu_pages) so an in-use root is zapped invalid while children are still created; the attacker controls both fault and reclaim sides of the race.\nPR:N - Exploitation requires only code running inside an already-running KVM guest (or equivalent guest-driven KVM_RUN activity); no host root, CAP_SYS_ADMIN, or direct /dev/kvm access is needed beyond what any cloud VM tenant or compromised guest process already has.\nUI:N - Once the attacker can execute in the guest, triggering the fault/reclaim sequence is entirely self-driven through guest memory and paging behavior with no action required from another user or administrator.\nS:C - Corrupting host KVM MMU active_mmu_pages/list state from guest-controlled faults crosses the guest-to-host virtualization boundary and can compromise the host kernel beyond the guest security domain, enabling VM escape-class impact.\nC:H - The demonstrated slab use-after-free and broken active-list invariant (invalid children left linked while __kvm_mmu_prepare_zap_page uses list_add instead of list_move) provide attacker-influenced host heap corruption that can be leveraged for arbitrary kernel memory reads.\nI:H - The same UAF and doubly-linked list corruption on host kvm_mmu_page objects are writable memory-corruption primitives suitable for control-flow or structure hijacking, not merely benign accounting errors.\nA:H - KASAN reports a host slab UAF with an 8-byte write in __kvm_mmu_get_shadow_page, and list corruption on active_mmu_pages can cause host oops, panic, or hang, denying service to the host and co-located VMs." } } }