To enable Oracle VirtualBox USB support for a user on Fedora or some other Linux distribution appliance, first install the VirtualBox Extensions Pack and then add the user to the vboxusers group.
# usermod -a -G vboxusers your-username
If the vboxusers group does not exist, create the group and add your username.
# groupadd vboxusers # usermod -a -G vboxusers your-username
Then reboot the Linux appliance and the user should be able to access USB devices.