The following FASTBUGS have been uploaded to

http://ftp.scientificlinux.org/linux/scientific/6x/i386/updates/fastbugs/
http://ftp.scientificlinux.org/linux/scientific/6x/x86_64/updates/fastbugs/

i386:
6x/i386/firefox-60.1.0-6.el6.i686.rpm

x86_64:
6x/x86_64/firefox-60.1.0-6.el6.i686.rpm
6x/x86_64/firefox-60.1.0-6.el6.x86_64.rpm