A Debian Linux developer warns all unfixed Intel sixth and seventh generation processors based on the Skylake and Kaby Lake architectures have a serious Hyper-Threading flaw. Users are advised to turn off Hyper-Threading in the BIOS as the bug can result in unpredictable system behavior, errors, data corruption, and data loss.
This advisory is about a processor/microcode defect recently identified
on Intel Skylake and Intel Kaby Lake processors with hyper-threading
enabled. This defect can, when triggered, cause unpredictable system
behavior: it could cause spurious errors, such as application and system
misbehavior, data corruption, and data loss.
It was brought to the attention of the Debian project that this defect
is known to directly affect some Debian stable users (refer to the end
of this advisory for details), thus this advisory.
Please note that the defect can potentially affect any operating system
(it is not restricted to Debian, and it is not restricted to Linux-based
systems). It can be either avoided (by disabling hyper-threading), or
fixed (by updating the processor microcode).
Due to the difficult detection of potentially affected software, and the
unpredictable nature of the defect, all users of the affected Intel
processors are strongly urged to take action as recommended by this
The HT bug affects all operating systems, more details can be found in the Debian advisory. Users running Windows will need to wait on an UEFI firmware upgrade that contains the CPU microcode update from Intel.