The issue is related to pointer dereference errors in the Linux kernel. It allows an attacker to access confidential data, compromise its integrity, and cause a denial of service. Specifically, with shadow paging enabled, the INVPCID instruction results in a call to `kvm mmu invpcid gva`. If INVPCID is executed with CR0.PG=0, the `invlpg` callback is not set, leading to a NULL pointer dereference.