X11 in Apple Mac OS X 10.5 through 10.5.1 does not properly handle when the “Allow connections from network client” preference is disabled, which allows remote attackers to bypass intended access restrictions and connect to the X server.
docs.info.apple.com/article.html?artnum=307430
lists.apple.com/archives/security-announce/2008/Feb/msg00002.html
secunia.com/advisories/28891
www.securityfocus.com/bid/27736
www.securitytracker.com/id?1019365
www.us-cert.gov/cas/techalerts/TA08-043B.html
www.vupen.com/english/advisories/2008/0495/references