Henrique de Moraes Holschuh unveiled a serious problem that may occur if you are using an Intel Skylake or Kaby Lake processors with Hyper-Threading. You can read his full article and advisory on the Debian mailing lists.
Apparently, a microcode bug in hyper-threaded Intel processors could “in some situations, dangerously misbehave when hyper-threading is enabled” which can lead to “application and system misbehavior, data corruption, and data loss”.
This affects processors from the sixth and seventh (Skylake and Kaby Lake) generations but only those which have Hyper-Threading. However, this is quite concerning as most models do have the Hyper-Threading technology. This includes the Core processors both for desktops and notebooks, the Xeon series and even some Pentiums such as G4560.
What is even more alarming is that this bug is not limited to Linux distributions such as Debian. It affects every operating system. Intel has updated its products’ documentation two months ago when the bug was initially discovered. The explanation is: “Under complex micro-architectural conditions, short loops of less than 64 instructions that use AH, BH, CH or DH registers as well as their corresponding wider register (eg RAX, EAX or AX for AH) may cause unpredictable system behaviour. This can only happen when both logical processors on the same physical processor are active.”
For now, you can protect yourself and your system by disabling Hyper-Threading. Skylake users could protect themselves by updating their CPU microcode. Unfortunately, users of the newer Kaby Lake models should disable Hyper-Threading. The Kaby Lake microcode updates are available only to system vendors so you should wait for a BIOS/UEFI
Meanwhile, you can check all Intel products over here: http://amzn.to/2nwU3e8