In the Ganges-Brahmaputra-Meghna delta, covering most of Bangladesh, more than 165 million people live in low-lying coasts facing major extreme climatic events, such as cyclones. This article reviews the current scientific literature publications (2007-2020) in order to define vulnerability in the context of coastal Bangladesh facing cyclonic flooding. Based on this review, a new metric, called the socio-spatial vulnerability index (SSVI), is defined as function of both the probability of the cyclonic flood hazard and the sensitivity of delta inhabitants. The main result shows that the districts of Shariatpur, Chandpur and Barisal situated in the tidal floodplain of the Ganges-Brahmaputra-Meghna delta are in the fourth quartile, i.e., highest category, the most vulnerable areas. These districts are very densely populated (from 870 up to 1400 inhabitants per square kilometer) and exposed to inundation hazards with a large number of vulnerability factors. Finally, the delta's mouth was identified as a very vulnerable area to cyclonic flooding as well.