xrdb.c in xrdb before 1.0.9 in X.Org X11R7.6 and earlier allows remote attackers to execute arbitrary commands via shell metacharacters in a hostname obtained from a (1) DHCP or (2) XDMCP message.
cgit.freedesktop.org/xorg/app/xrdb/commit/?id=1027d5df07398c1507fb1fe3a9981aa6b4bc3a56
lists.fedoraproject.org/pipermail/package-announce/2011-April/057928.html
lists.freedesktop.org/archives/xorg-announce/2011-April/001635.html
lists.freedesktop.org/archives/xorg-announce/2011-April/001636.html
lists.opensuse.org/opensuse-security-announce/2011-04/msg00002.html
secunia.com/advisories/44010
secunia.com/advisories/44012
secunia.com/advisories/44040
secunia.com/advisories/44082
secunia.com/advisories/44122
secunia.com/advisories/44123
secunia.com/advisories/44193
slackware.com/security/viewer.php?l=slackware-security&y=2011&m=slackware-security.465748
www.debian.org/security/2011/dsa-2213
www.mandriva.com/security/advisories?name=MDVSA-2011:076
www.redhat.com/support/errata/RHSA-2011-0432.html
www.redhat.com/support/errata/RHSA-2011-0433.html
www.securityfocus.com/bid/47189
www.securitytracker.com/id?1025317
www.ubuntu.com/usn/USN-1107-1
www.vupen.com/english/advisories/2011/0880
www.vupen.com/english/advisories/2011/0889
www.vupen.com/english/advisories/2011/0906
www.vupen.com/english/advisories/2011/0929
www.vupen.com/english/advisories/2011/0966
www.vupen.com/english/advisories/2011/0975
bugzilla.redhat.com/show_bug.cgi?id=680196
exchange.xforce.ibmcloud.com/vulnerabilities/66585
lwn.net/Articles/437150/