MySQL 5.1, which is packaged in RHEL-6 as mysql packages, is planned to reach end of life in Dec 2013:
After that date, we will not be able to provide security updates for those packages as upstream refuses to provide any details on security fixes they do upstream. See bug 843043 for further details.
Similar problem affected RHEL-5 MySQL 5.0 packages and was addressed by introducing MySQL 5.5 packaged as software collection (bug 843043, comment 23).
For RHEL-6, MySQL 5.5 is already available via RHSCL-1:
However, RHSCL is only available for x86_64, so it does not address the problem for other non-x86_64 RHEL-6 architectures.
More information can be found here: