ASA-2019-00272 – FreeBSD: Microarchitectural Data Sampling (MDS)

Modern processors make use of speculative execution, an optimization technique which performs some action in advance of knowing whether the result will actually be used. On some Intel processors utilizing speculative execution a local process may be able to infer stale information from microarchitectural buffers to obtain a memory disclosure. An attacker may be able to read secret data from the kernel or from a process when executing untrusted code (for example, in a web browser).