Note the prior concerns are still just as true today as they were a few years ago — graphics drivers are still relatively easy to find crash bugs in, leading browser vendors to try and hack around and avoid hitting those bugs in all too many cases. :(
You should, until proven otherwise. If it crashes because it's reading an invalid memory location (for instance), it's a matter of time before someone figures out how to place executable code there.
I have no problem with MS's original position. WebGL forces your hardware drivers to run random code downloaded from the internet. I'm frankly surprised that the other browser vendors ran ahead with it so quickly and that we haven't heard about any exploits caused by it.
Also, if I'm not mistaken Chrome shipped first: and they'd done masses of fuzzing of both their code and the drivers. Nobody really rushed into it, everyone keeping it off by default for an unusually long time to catch issues before shipping.
It's fine that it took them time and they wanted to do it properly. It is however annoying that they did not give any forward notice of their intention to implement WebGL and have not been active in the standards bodies at all. For example, Microsoft input on the safety aspects could have been very useful.
They've apparently reversed that stance.
I don't disagree with Microsoft's point in this article. http://blogs.technet.com/b/srd/archive/2011/06/16/webgl-cons...
I assume that they've decided to work towards solving the security issues instead of simply staying away from the issue.
Long term I hope this means more stable and reliable video drivers :)