For a typical user, the browser presents the highest risk, but we have yet to see proof of concept code that exploits this vulnerability through JavaScript – and browser vendors have started issuing patches as well (for example, Mozilla has issued a new version of Firefox, 57.0.4, where they have decreased the precision of time sources to make attacks such as Spectre more difficult or impossible). If you run stuff as Administrator: Spectre makes no difference for you really.

In other words: the world will end over the weekend.

Source: Meltdown and Spectre: clearing up the confusion – SANS Internet Storm Center