The pa_rtp_recv function in modules/rtp/rtp.c in the module-rtp-recv module in PulseAudio 5.0 and earlier allows remote attackers to cause a denial of service (assertion failure and abort) via an empty UDP packet.
http://www.securityfocus.com/bid/67814
http://www.mandriva.com/security/advisories?name=MDVSA-2015:134
http://secunia.com/advisories/60624
http://seclists.org/oss-sec/2014/q2/437