A Remote Crash issue was discovered in Asterisk Open Source 13.x before 13.18.4, 14.x before 14.7.4, and 15.x before 15.1.4 and Certified Asterisk before 13.13-cert9. Certain compound RTCP packets cause a crash in the RTCP Stack.
https://www.debian.org/security/2017/dsa-4076
https://issues.asterisk.org/jira/browse/ASTERISK-27429
https://issues.asterisk.org/jira/browse/ASTERISK-27382
http://www.securitytracker.com/id/1040009