That's strange I followed the instructions here.

http://centosnow.blogspot.com/2014/09/critical-bash-updates-for-centos-5.html?m=1

Updated no problem.

Then Doug pointed out yum update bash. Just to be double sure I did that and it saw something like no update necessary.

I just just got done taking on my repeater we had Zello, zoiper, and RF going it was a beautiful thing.