If there is an Asterisk crash that you can reproduce by sending packets, then you can submit it to Sangoma for review. We package Asterisk as is, we are not developers on it. Your description is also too broad, is it IAX, SIP or PJSIP that is crashing? You can find out via backtrace... if its IAX, and you do not use IAX, then disable chan_iax... I do not think its PJSIP as Issabel does not come bundled with PJSIP by default, unless you specifically enable it... you do not say either... if its chan_sip, then perhaps you won't have luck reporting bugs to Asterisk as it is being deprecated and not maintained any longer, in that case you should wait for the release with pjsip support, (and then deal with all of the pjsip bugs , that has many more than chan_sip and they are being constantly being patched/updated by Sangoma).