CVE-2026-64284

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

KVM: x86: Ensure vendor's exit handler runs before fastpath userspace exits

Move the handling of fastpath userspace exits into vendor code to ensure

KVM runs vendor specific operations that need to run before userspace gains

control of the vCPU. E.g. for VMX (and soon to be for SVM as well), KVM

needs to flush the PML buffer prior to exiting to userspace, otherwise any

memory written by the final KVM_RUN might never be flagged as dirty.

Note, waiting to snapshot CR0 and CR3 until svm_handle_exit() is flawed in

general, as that risks consuming stale state in a fastpath handler. That

will be addressed in a future change.