Did you think Meltdown was bad? Unprivileged applications being able to read kernel memory at speeds possibly as high as megabytes per second was not a good thing.

Meet the Windows 7 Meltdown patch from January. It stopped Meltdown but opened up a vulnerability way worse ... It allowed any process to read the complete memory contents at gigabytes per second, oh - it was possible to write to arbitrary memory as wel

No fancy exploits were needed. Windows 7 already did the hard work of mapping in the required memory into every running process. Exploitation was just a matter of read and write to already mapped in-process virtual memory. No fancy APIs or syscalls required - just standard read and write!

Only Windows 7 x64 systems patched with the 2018-01 or 2018-02 patches are vulnerable. If your system isn't patched since December 2017 or if it's patched with the 2018-03 patches or later it will be secure.

http://blog.frizk.net/2018/03/total-meltdown.html?m=1