CVE-2019-3016: Race Condition

A flaw was found in the way Linux kernel's KVM hypervisor handled deferred TLB flush requests from guest. A race condition may occur between the guest issuing a deferred TLB flush request to KVM, and then KVM handling and acknowledging it. This may result in invalid address translations from TLB being used to access guest memory, leading to a potential information leakage issue. An attacker may use this flaw to access guest memory locations that it should not have access to.

In a Linux KVM guest that has PV TLB enabled a process in the guest kernel may be able to read memory locations from another process in the same guest. This problem is limit to the host running linux kernel 4.10 with a guest running linux kernel 4.16 or later. The problem mainly affects AMD processors but Intel CPUs cannot be ruled out.

— Microsoft

In a Linux KVM guest that has PV TLB enabled, a process in the guest kernel may be able to read memory locations from another process in the same guest. This problem is limit to the host running linux kernel 4.10 with a guest running linux kernel 4.16 or later. The problem mainly affects AMD processors but Intel CPUs cannot be ruled out.