It says the repository is unverified and not the software.
Did you install any additional repositories?
The repositories are usually checked with a PGP key file. Something wrong with your key files maybe?
It normally looks like this:
Code:
[fedora]
name=Fedora $releasever - $basearch
failovermethod=priority
#baseurl=http://download.fedoraproject.org/pub/fedora/linux/releases/$releasever/Everything/$basearch/os/
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=fedora-$releasever&arch=$basearch
enabled=1
metadata_expire=7d
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-$basearch
You might get rid of the message if you disable the gpgcheck, but this would only disable the message and not the root of the problem!