We have a google group for all automotive security newsletters
Escrypt Security Blog - Nice security blog from Escrypt.
Keen Security Lab Blog - Blog created by Keen Security Lab of Tencent that posts research on car security.
Security Weekly - Excellent podcast covering all ranges of security, with some episodes focusing portions on vehicle security from cars to drones.
TrustedSec Podcast - From the people at TrustedSec, leaders in Social Engineering, their episodes often go into recent vehicle vulnerabilities and exploits.
SANS Internet Storm Center - the ISC run a regular podcast going into the latest vulnerabilities and security news.
Security Ledger - A podcast focusing on interviewing security experts about topics related to security.