csstart program in iCal 2.1 Patch 2 uses relative pathnames to install the libsocket and libnsl libraries, which could allow the icsuser account to gain root privileges by creating a Trojan Horse library in the current or parent directory.
https://exchange.xforce.ibmcloud.com/vulnerabilities/5757
https://euvd.enisa.europa.eu/vulnerability/EUVD-2000-1060
http://www.securityfocus.com/bid/1769
http://www.atstake.com/research/advisories/2000/a100900-1.txt