blogspot.com and firefox 3 cookies

Since upgrading to Firefox 3 when logging into blogger.com then viewing my own blog at blogspot.com I no longer had the options in the top right corner to add new posts and the edit button at the bottom of my posts.

This was due to the fact that I have disabled 3rd party cookies, which meant that my credentails for being logged into blogger.com could not be read by blogspot.com

By adding blogger.com to the allowed list I now remain logged in when viewing my blog on blogspot.com. Is this a security risk can any site now read my blogger.com cookies?

Here is the setting that got it working again.