PT-2026-29485 · Linux · Linux

Published 2026-04-01 · Updated 2026-04-01 · CVE-2026-23402

NVD

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86/mmu: Only WARN in direct MMUs when overwriting shadow-present SPTE

Adjust KVM's sanity check against overwriting a shadow-present SPTE with a another SPTE with a different target PFN to only apply to direct MMUs, i.e. only to MMUs without shadowed gPTEs. While it's impossible for KVM to overwrite a shadow-present SPTE in response to a guest write, writes from outside the scope of KVM, e.g. from host userspace, aren't detected by KVM's write tracking and so can break KVM's shadow paging rules.

------------[ cut here ]------------ pfn != spte to pfn(*sptep) WARNING: arch/x86/kvm/mmu/mmu.c:3069 at mmu set spte+0x1e4/0x440 [kvm], CPU#0: vmx ept stale r/872 Modules linked in: kvm intel kvm irqbypass CPU: 0 UID: 1000 PID: 872 Comm: vmx ept stale r Not tainted 7.0.0-rc2-eafebd2d2ab0-sink-vm #319 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:mmu set spte+0x1e4/0x440 [kvm] Call Trace: ept page fault+0x535/0x7f0 [kvm] kvm mmu do page fault+0xee/0x1f0 [kvm] kvm mmu page fault+0x8d/0x620 [kvm] vmx handle exit+0x18c/0x5a0 [kvm intel] kvm arch vcpu ioctl run+0xc55/0x1c20 [kvm] kvm vcpu ioctl+0x2d5/0x980 [kvm] x64 sys ioctl+0x8a/0xd0 do syscall 64+0xb5/0x730 entry SYSCALL 64 after hwframe+0x4b/0x53 ---[ end trace 0000000000000000 ]---

Related Identifiers

CVE-2026-23402

Affected Products

Linux

References · 2

• https://nvd.nist.gov/vuln/detail/CVE-2026-23402 · Security Note
• https://git.kernel.org/stable/c/df83746075778958954aa0460cca55f4b3fc9c02 · Note