Abstract: The rapid evolution of information systems continuously introduces new vulnerability types, especially those arising from the signal-information conversion processes at the interface between physical and digital realms. These vulnerabilities pose challenges for systematic analysis and detection. This article introduces the term “out-of-band vulnerabilities” to characterize such flaws, examining their conceptual foundations, causative mechanisms, current research landscape, and future directions. This article provides a valuable reference framework for addressing out-of-band vulnerabilities and enhancing the comprehensive vulnerability taxonomy.