I've noticed that every once in a few days (sometimes daily) my CPU spikes to a 120% or such usage when any of my browsers are open.
The scenario is weird, today I was watching a movie using VLC player and I saw my battery starting to drain unusually fast and my fans running out of control, I open up the Activity Monitor and see that Safari Networking is clogging up my CPU time and usage (100%). My Safari was open but in the background with a few random websites such as Stack Overflow, none Flash-related apps or something along the lines. This was happening on Chrome way too often under the Process Name of Chrome Helper, but with a slightly greater CPU usage.
When I force shutdown the processes either via Activity Monitor or their PID everything returns to normal. Any clues? Happy to post any logs necessary.
macOS High Sierra 10.13, MacBook Pro (13-inch, 2017, Two Thunderbolt 3 ports)