PS4 3.50 Webkit Exploit followed by a PS4 3.50 Webkit Crash, and now PlayStation 4 developer NextGenModderPS4 shared a PS4 4.0 Beta WebKit crash demo video with details below!
From the video's caption / comments, to quote Hybrid7Theory: PS4 4.0 BETA WEBKIT CRASH
The webkit crash works on 4.0 and the poc test succeeded somehow. Enjoy. Sony might take down the video so use a a video extractor to download the video.
Same as 3.55. Used it for a full day no problems then went back to 3.55. If you plan on using the WebKit playground or linux use ps proxy by red eye so you don't have to update and still go online.
Thanks to @B7U3 C50SS for the news in the Shoutbox and to @NextGenModzPS4 for the demo video!