Except on Linux. As an anecdote, as recently as January, visiting any WebGL sites that used any shaders would reliably panic my kernel with NVidia hardware and the NVidia binary blob. I then switched to Intel hardware which is much more stable but also shows how much variance there is here.

For me to be comfortable with WebGL, we'll have to really train graphics card manufacturers to take security issues as seriously as web developers do. That isn't going to happen any time soon.