The ifx_load_internal function in IBM Informix Dynamic Server (IDS) allows remote authenticated users to execute arbitrary C code via the DllMain or _init function in a library, aka "C code UDR."
https://exchange.xforce.ibmcloud.com/vulnerabilities/28129
http://www.vupen.com/english/advisories/2006/3077
http://www.securityfocus.com/bid/19264
http://www.securityfocus.com/archive/1/443184/100/0/threaded
http://www.securityfocus.com/archive/1/443133/100/0/threaded