CVE-2026-98164

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

KVM: x86/mmu: Check write tracking in all address spaces

kvm gfn is write tracked() checks only the supplied memslot, but page tracking is per-address-space and shadow pages are shared across all address spaces. With SMM, a GFN can therefore be write-tracked in one address space and appear untracked through the other.

Check the supplied slot first, then the slot for the other address space. This ensures all callers honor write tracking regardless of the active address space. In particular, it prevents mmu try to unsync pages() from marking an upper-level shadow page unsync and eventually triggering the BUG in pte list remove().

[invert direction of the conditional. - Paolo]