Comments are very welcome on bert@hubertnet.nl or @bert_hu_bert. Update: several constructive remarks have been used to improve this text. Thanks! In this post I will attempt to fully explain the Spectre and Meltdown vulnerabilities in an accessible way. I decided to write it up after I realised it took me more than a day to figure it out, even though I’ve been doing security related stuff on CPUs for 20 years.