Heap-based buffer overflow in the parse_string function in libs/esl/src/esl_json.c in FreeSWITCH before 1.4.23 and 1.6.x before 1.6.2 allows remote attackers to execute arbitrary code via a trailing \u in a json string to cJSON_Parse.
https://freeswitch.org/stash/projects/FS/repos/freeswitch/commits/cf8925
http://www.securityfocus.com/archive/1/536569/100/0/threaded