Throughout the blogosphere there’s been reports of an issue with ASP.NET that will bring a site to it’s knees – or so, it’s been overblown and reported as such.
Microsoft has released an advisory here that discusses the matter.
The workaround for now is something that any public website should’ve been doing anyway. That is, implement a custom error handling page and suppress revealing detailed errors. This is a normal part of a security audit and if you follow the STRIDE threat modeling you should have this as part of your checklist of things that you should ensure your following.