If you use Safari as your RSS reader, you should know that there is a known security issue that can allow a hacker to gain access to personal information on you computer. At this time Apple hasn't released a patch that fixes this vulnerability. But there is a simple change you can make to your Safari preferences that will protect you. If you are using Safari as your RSS reader, you should stop until a patch is available.

To change your default RSS reader to be something else, open Safari and go to Safari > Preferences... in the menu bar. Then click on the RSS tab. At the top of the panel you can then choose a different application to act as your default RSS reader.