Microsoft have now release the hotfix for the security vulnerability found in ASP.Net.
I would advise anyone running and ASP.Net sites to run Windows Update on their servers and install the hotfix ASAP.
As with before more information about the hotfix can be found on Scott Gu’s blog at http://weblogs.asp.net/scottgu/archive/2010/09/30/asp-net-security-fix-now-on-windows-update.aspx