scponlyc in scponly 4.1 and earlier, when the operating system supports LD_PRELOAD mechanisms, allows local users to execute arbitrary code with root privileges by creating a chroot directory in their home directory, hard linking to a system setuid application, and using a modified LD_PRELOAD to modify expected function calls in the setuid application.
https://exchange.xforce.ibmcloud.com/vulnerabilities/23874
http://www.securityfocus.com/bid/16051
http://www.gentoo.org/security/en/glsa/glsa-200512-17.xml
http://www.debian.org/security/2006/dsa-969
http://sublimation.org/scponly/#relnotes
http://secunia.com/advisories/18829