https://arstechnica.com/gadgets/2018/02/intel-ships-hopefully-stable-microcode-for-skylake-kaby-lake-coffee-lake/

Intel reports that it has developed a stable microcode update to address the Spectre flaw for its Skylake, Kaby Lake, and Coffee Lake processors in all their various variants.

The microcode updates help address Spectre variant 2 attacks. Spectre variant 2 attacks work by persuading a processor's branch predictor to make a specific bad prediction about which code will be executed. This bad prediction can then be used to infer the value of data stored in memory, which, in turn, gives an attacker information that they shouldn't otherwise have. The microcode update is designed to give operating systems greater control over the branch predictor, enabling them to prevent one process from influencing the predictions made in another process.