During February 2026, Bjrxyz focused on backend security for the coturn/coturn repository, addressing a critical vulnerability in the web admin authentication logic. Using C programming and backend development expertise, Bjrxyz identified and corrected a reversed password check that previously allowed unauthorized access to the admin interface. The urgent patch, linked to issues #363 and #1216, ensured that only valid credentials could grant administrative access, thereby reducing the risk of credential abuse and preserving system integrity. This work demonstrated rapid triage, effective security debugging, and collaborative code review, reflecting a focused and impactful contribution to authentication security hardening.