If you do
yum check-update
is it presenting a newer version of bind?
yum update bind\*
@Ben29: That's no use. If yum check-update will not show any version of bind, neither will your command.
@Blog: Check your /etc/yum.conf maybe bind* is excluded in there. Only bind-chroot* should be excluded.
If bind is excluded, remove bind (leave bind-chroot* in place) and save the file.
After that run yum update bind again.
No dont do that. Centos does not use the newest versions of software. Why do you think it needs to be upgraded?