from bpy import context

def color_from_active():
    active = context.active_object
    selection = context.selected_objects
    objs = [o for o in selection if not o is active and o.type == 'MESH']
    
    if not objs or not 'OBJECT' in context.mode:
        print("No selection")
        return

    # set to True to use color from active (assumes any vertex is colored)
    color_from_active = True

    # or use a solid color (r,g,b,a)
    color = [0,0,1,1]

    if color_from_active:
        if active.data.vertex_colors:
            v_col = active.data.vertex_colors[0]
            color = list(v_col.data[0].color)
    else:
        objs.append(active)
            
    if objs:
        for o in objs:
            if not o.data.vertex_colors:
                v_col = o.data.vertex_colors.new()
                
            else:
                v_col = o.data.vertex_colors[0]
                
            for data in v_col.data:
                data.color = color
        
if __name__ == "__main__":
    color_from_active()