{"id":"CVE-2026-23402","summary":"KVM: x86/mmu: Only WARN in direct MMUs when overwriting shadow-present SPTE","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86/mmu: Only WARN in direct MMUs when overwriting shadow-present SPTE\n\nAdjust KVM's sanity check against overwriting a shadow-present SPTE with a\nanother SPTE with a different target PFN to only apply to direct MMUs,\ni.e. only to MMUs without shadowed gPTEs.  While it's impossible for KVM\nto overwrite a shadow-present SPTE in response to a guest write, writes\nfrom outside the scope of KVM, e.g. from host userspace, aren't detected\nby KVM's write tracking and so can break KVM's shadow paging rules.\n\n  ------------[ cut here ]------------\n  pfn != spte_to_pfn(*sptep)\n  WARNING: arch/x86/kvm/mmu/mmu.c:3069 at mmu_set_spte+0x1e4/0x440 [kvm], CPU#0: vmx_ept_stale_r/872\n  Modules linked in: kvm_intel kvm irqbypass\n  CPU: 0 UID: 1000 PID: 872 Comm: vmx_ept_stale_r Not tainted 7.0.0-rc2-eafebd2d2ab0-sink-vm #319 PREEMPT\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n  RIP: 0010:mmu_set_spte+0x1e4/0x440 [kvm]\n  Call Trace:\n   \u003cTASK\u003e\n   ept_page_fault+0x535/0x7f0 [kvm]\n   kvm_mmu_do_page_fault+0xee/0x1f0 [kvm]\n   kvm_mmu_page_fault+0x8d/0x620 [kvm]\n   vmx_handle_exit+0x18c/0x5a0 [kvm_intel]\n   kvm_arch_vcpu_ioctl_run+0xc55/0x1c20 [kvm]\n   kvm_vcpu_ioctl+0x2d5/0x980 [kvm]\n   __x64_sys_ioctl+0x8a/0xd0\n   do_syscall_64+0xb5/0x730\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n   \u003c/TASK\u003e\n  ---[ end trace 0000000000000000 ]---","modified":"2026-08-12T03:51:18.063035787Z","published":"2026-04-01T08:36:33.366Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23402.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/a1e0f7150639bc30a8e75476d1c7daab77d44992"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bab090e8fd5607f77379ea78b9d0c683cb1538a9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/df83746075778958954aa0460cca55f4b3fc9c02"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23402.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23402"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"11d45175111d933c5175acc28e56af2213dd5cd6"},{"fixed":"bab090e8fd5607f77379ea78b9d0c683cb1538a9"},{"fixed":"a1e0f7150639bc30a8e75476d1c7daab77d44992"},{"fixed":"df83746075778958954aa0460cca55f4b3fc9c02"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23402.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.16.0"},{"fixed":"6.18.21"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23402.json"}}],"schema_version":"1.9.0"}