CVE-2026-89928 KVM: x86/mmu: Consume the locked rmap value in the lockless rmap walk

In the Linux kernel, the following vulnerability has been resolved: KVM: x86/mmu: Consume the locked rmap value in the lockless rmap walk kvmrmaplock deliberately elides the rmap lock when it observes an empty rmap. In that case kvmrmaplockreadonly also re-enables preemption and returns zero, so...

CVE-2026-89928

CVE-2026-89928 is a slab use-after-free in the Linux kernel's KVM x86/mmu subsystem. The root cause is a race condition in the lockless reverse-mapping (rmap) walk: kvm_rmap_age_gfn_range() ignores the value returned by kvm_rmap_lock_readonly() and instead re-reads the rmap head via rmap_get_firs...