According to a mailing list post on the 14th, there are infrastructure problems with the Fedora network, and users are advised not to download and/or install updates. ZDNet’s Zero Day blog suggests this might be security-related. 

While I’d normally think this is just a rumor and leave it at that until more information is available, it’s been several days now and the latest update contains some details that might hint at a security problem:

** New SSH fingerprint for Fedora Hosted:
I’m amazed this hasn’t seen more media coverage yet, especially since the Fedora project has been so silent about what exactly is going on.