Worst digital security issue I've ever seen or heard of. Synopsis: Two different vulnerabilities, both caused by architectural flaws in speculative execution hardware (e.g, "branch prediction.") One flaw affects most, but not all CPUs manufactured in the past 10 years (but not AMD,) is easily exploitable, but can be fixed using a software patch (which may degrade performance by up to 30%.) The other cannot be fixed other than by designing new CPU hardware, but is rather difficult to exploit (all modern processors are affected regardless of ISA or manufacturer, without exception.)