(RHSA-2011:1155) Important: xorg-x11 security update

X.Org is an open source implementation of the X Window System. It provides
the basic low-level functionality that full-fledged graphical user
interfaces are designed upon. These xorg-x11 packages also provide the
X.Org libXfont runtime library.

A buffer overflow flaw was found in the way the libXfont library, used by
the X.Org server, handled malformed font files compressed using UNIX
compress. A malicious, local user could exploit this issue to potentially
execute arbitrary code with the privileges of the X.Org server.
(CVE-2011-2895)

Users of xorg-x11 should upgrade to these updated packages, which contain
a backported patch to resolve this issue. All running X.Org server
instances must be restarted for the update to take effect.