Enclave data disclosure via stale xAPIC reads

Information disclosure in Intel processors with SGX allows privileged local users to infer enclave data through legacy xAPIC MMIO reads. Incorrectly aligned reads from the physical xAPIC MMIO page can return stale data previously accessed by the same core, which an enclave can unintentionally process outside its protected memory range. Exploitation requires control of the host OS or VMM to map xAPIC outside the enclave range; the resulting exposure is limited to confidentiality.