This bug is not a regression. I just cloned it from RHEL6 so we have it reported in the case curl will be fixed again in future relaseses.
Thanks for the bug report. We are sorry, but it is too late in the RHEL-5 release cycle. I am closing this bugzilla WONTFIX. If the issue is critical for your business, please contact Red Hat Product Support - and inform them about this bugzilla. For RHEL-6, this bug was fixed in curl-7.19.7-26.el6.