IBM Informix Dynamic Server (IDS) allows remote authenticated users to create and overwrite arbitrary files via the (1) LOTOFILE and (2) trl_tracefile_set functions, and the (3) "SET DEBUG FILE" commands.
https://exchange.xforce.ibmcloud.com/vulnerabilities/28383
http://www.securityfocus.com/archive/1/443216/100/0/threaded
http://www.securityfocus.com/archive/1/443133/100/0/threaded