Thanks for reporting a potential issue of our project! Just for clarification, Kamailio does not contain code from any other project in this case, I tracked the related code to be dated back to 2002 (when the project had its original name `SER` and the project you named didn't exist). The other project probably inherited from this one when it was forked.
Anyhow, I tried to reproduce with the sample SIP message from the web and I didn't get any crash with Kamailio git master branch, it prints error messages:
``` 3(142428) ERROR: {1 9 REGISTER 83ZZolAa} <core> [core/parser/digest/digest.c:323]: find_credentials(): error while parsing credentials 3(142428) ERROR: {1 9 REGISTER 83ZZolAa} auth [api.c:73]: pre_auth(): Error while looking for credentials 3(142428) DEBUG: {1 9 REGISTER 83ZZolAa} auth_db [authorize.c:261]: digest_authenticate_hdr(): error or bad credentials ```
Then sends back SIP 401 response and continues to work normally. Kamailio was started with MySQL backed and user authentication done with `auth_db` module (like default `kamailio.cfg` with defined `WITH_MYSQL` and `WITH-AUTH`).
Can you provide (here or better via email to miconda@gmail.com) a SIP message related to this issue that causes a crash for Kamailio git master branch?