The mobile core team at @sipgate has disclosed a #SIP parsing bug in #mediatek's #VoLTE/ #VoWifi stack which leads to a null-pointer-dereference and ultimately Denial of Service of VoLTE telephony for the affected devices. Around 40 baseband chips were affected which were deployed to over 1000 devices since 2017.

https://www.sipgate.de/blog/sipgate-discovers-null-pointer-dereference-in-mediatek-volte-stack-firmware

Thanks to @hendrikkiel for the great cooperation!