If you are using antivirus or security software from Symantec or Norton, you should update your software immediately due to a serious flaw in the software that has been disclosed.
If you are a home user and you are using Norton Antivirus, Norton 360, or any other security/anti-virus product with the Norton or Symantec name on it, you should perform a Live Update immediately in order to remove the vulnerability from your system.
Remember that anti-virus is only one piece of the puzzle to help keep your computer and network safe. You should always keep Windows up to date, minimize your security rights and backup your data. Read more in our article here.
The business page with technical information from Symantec is located here.