This bug has been copied from bug #877348 and has been proposed to be backported to 5.9 z-stream (EUS).
Fix is built into libxml2-2.6.26-2.1.21.el5_9.2, Daniel
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHBA-2013-0591.html
I think this update caused a regression: https://bugzilla.redhat.com/show_bug.cgi?id=924785