Worked on security hardening for the cloudamqp/lavinmq repository, focusing on SSL/TLS client certificate handling within SNI contexts. Addressed a bug where SSL options such as verify_mode and client CA lists were not properly preserved when switching SNI contexts, which could allow invalid client certificates to bypass mTLS verification. The solution involved explicitly invoking SSL_set_verify, SSL_set_verify_depth, and SSL_set_client_CA_list to enforce correct verification paths. This backend development effort, using Crystal and network programming skills, improved the robustness and security posture of LavinMQ, ensuring more reliable multi-tenant messaging by mitigating risks associated with improper SSL/TLS option propagation.