The CentOS team has been looking at the issue called out in these stories:
http://threatpost.com/en_us/blogs/trivial-password-flaw-leaves-mysql-databas...
http://arstechnica.com/information-technology/2012/06/security-flaw-in-mysql...
http://www.net-security.org/secworld.php?id=13076
According to the upstream provider EL4, EL5 and EL6 are not impacted by the above issue:
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2012-2122
Thanks, Johnny Hughes