Yes I have been reading about it this morning. This is the break of the most sacred governance in history of modern computing and operating systems. That the core operating system (kernel)'s data is always private and no application can read it.
From the information, it seems like a really, really stupid bug. Modern CPUs perform what is called speculative execution. When they get to a branch in the code, the chase both conditions and pre-execute what is there. Then depending on which condition is true, they discard the code from the other branch. Problem here is that there is no check to see if either one of those paths are accessing privileged kernel code. They CPU (which is even more privileged than the operating system) appears to happily fetch that memory location. It is only after it gets to the target instruction that it check to see if the right privilege is there to allow that.
The fix is to have the kernel have its own page table (the thing that allows all of this virtual memory magic to work) which takes away the ability of the user program to see any memory belonging to the kernel. Problem with this is that the table needs to reload on every call to the operating system to perform a function. This can really slow down programs that are NOT compute-bound. Everyday stuff like typing in this browser cause tons of these "system calls" to fetch keyboard data, write them to files, send them on networks, display them, etc. So the impact will be largest on them.
Wonder if new CPUs with this fix are already here and if so, then Intel has known about this problem for a long time. If not, then the problem will continue for a while.
Per article, AMD says this is not a problem in their CPUs so they immediately gain a market advantage.