start_kdeinit in KDE 3.5.5 through 3.5.9, when installed setuid root, allows local users to cause a denial of service and possibly execute arbitrary code via "user-influenceable input" (probably command-line arguments) that cause start_kdeinit to send SIGUSR1 signals to other processes.
https://exchange.xforce.ibmcloud.com/vulnerabilities/42039
http://www.vupen.com/english/advisories/2008/1370/references
http://www.ubuntu.com/usn/usn-608-1
http://www.securitytracker.com/id?1019924
http://www.securityfocus.com/bid/28938
http://www.mandriva.com/security/advisories?name=MDVSA-2008:097
http://www.kde.org/info/security/advisory-20080426-2.txt
http://security.gentoo.org/glsa/glsa-200804-30.xml
http://secunia.com/advisories/30113
http://secunia.com/advisories/29977
http://secunia.com/advisories/29951
http://lists.opensuse.org/opensuse-security-announce/2008-05/msg00000.html