The Asterisk project reports:
AST-2018-004 - When processing a SUBSCRIBE request the res_pjsip_pubsub module stores the accepted formats present in the Accept headers of the request. This code did not limit the number of headers it processed despite having a fixed limit of 32. If more than 32 Accept headers were present the code would write outside of its memory and cause a crash. AST-2018-005 - A crash occurs when a number of authenticated INVITE messages are sent over TCP or TLS and then the connection is suddenly closed. This issue leads to a segmentation fault.