We explored the critical cybersecurity challenges that smart buildings are facing as they become increasingly interconnected through IoT systems, cloud platforms, and digital automation. We began by explaining vulnerabilities across software, hardware, networks, and human behavior, showing how these weaknesses if left unaddressed can be exploited by cybercriminals, leading to serious security breaches. We categorized the types of threats facing smart buildings, such as ransomware, IoT device hacking, network intrusions, and human centered attacks like phishing. To be able to face these risks, we outlined essential cybersecurity measures across four domains of software, hardware, network, and human security practices. We then highlighted the unique risks that smart commercial buildings face, due to their complex ecosystems and decentralized management. Recognizing the persistent cybersecurity gaps, we explained the necessity of rigorous gap analysis to proactively address vulnerabilities. Finally, we introduced key cybersecurity services and frameworks, including ISA/IEC 62443, Supplier Cyber Trust Level, and UL CAP certifications, providing organizations with structured pathways to secure their smart building infrastructures against evolving cyber threats.