An updated xorg-x11-server-utils package that fixes one security issue is now available for Red Hat Enterprise Linux 5 and 6.
The Red Hat Security Response Team has rated this update as having moderate security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) associated with each description below.
The xorg-x11-server-utils package contains a collection of utilities used to modify and query the runtime configuration of the X.Org server. X.Org is an open source implementation of the X Window System.
A flaw was found in the X.Org X server resource database utility, xrdb. Certain variables were not properly sanitized during the launch of a user's graphical session, which could possibly allow a remote attacker to execute arbitrary code with root privileges, if they were able to make the display manager execute xrdb with a specially-crafted X client hostname. For example, by configuring the hostname on the target system via a crafted DHCP reply, or by using the X Display Manager Control Protocol (XDMCP) to connect to that system from a host that has a special DNS name.
Red Hat would like to thank Matthieu Herrb for reporting this issue. Upstream acknowledges Sebastian Krahmer of the SuSE Security Team as the original reporter.
Users of xorg-x11-server-utils should upgrade to this updated package, which contains a backported patch to resolve this issue. All running X.Org server instances must be restarted for this update to take effect.