Asterisk Project Security Advisory – It is possible to trigger a crash in Asterisk by sending a SIP SUBSCRIBE request with unexpected mixes of headers for a given event package. The crash occurs because Asterisk allocates data of one type at one layer and then interprets the data as a separate type at a different layer. The crash requires that the SUBSCRIBE be sent from a configured endpoint, and the SUBSCRIBE must pass any authentication that has been configured. Note that this crash is Asterisk’s PJSIP-based res_pjsip_pubsub module and not in the old chan_sip module.