Intel CPUs afflicted with simple data-spewing spec-exec vulnerability
Spectre attacks have so far only been observed at the nation-state level in the wild. If you're truly paranoid about being in the first wave of victims, disable Javascript and other active content on non-white listed pages.  At some point processors are going to have to drop into a non-speculative security mode when dealing with vulnerable data like passwords and handshakes, and pop back out of it when they're done.