The Nagios process in (1) Nagios before 3.0.5 and (2) op5 Monitor before 4.0.1 allows remote authenticated users to bypass authorization checks, and trigger execution of arbitrary programs by this process, via an (a) custom form or a (b) browser addon.
https://www.ubuntu.com/usn/USN-698-3/
http://www.vupen.com/english/advisories/2009/1256
http://www.vupen.com/english/advisories/2008/3364
http://www.vupen.com/english/advisories/2008/3029
http://www.ubuntu.com/usn/USN-698-1
http://www.securitytracker.com/id?1022165
http://www.securityfocus.com/bid/32156
http://www.openwall.com/lists/oss-security/2008/11/06/2
http://www.op5.com/support/news/389-important-security-fix-available-for-op5-monitor
http://www.nagios.org/development/history/nagios-3x.php
http://security.gentoo.org/glsa/glsa-200907-15.xml
http://secunia.com/advisories/35002