diff --git a/backends/imgui_impl_vulkan.cpp b/backends/imgui_impl_vulkan.cpp
index 2de6b40301bd..0b4b2663d6b3 100644
--- a/backends/imgui_impl_vulkan.cpp
+++ b/backends/imgui_impl_vulkan.cpp
@@ -259,7 +259,7 @@ static void CreateOrResizeBuffer(VkBuffer& buffer, VkDeviceMemory& buffer_memory
 
     err = vkBindBufferMemory(v->Device, buffer, buffer_memory, 0);
     check_vk_result(err);
-    p_buffer_size = new_size;
+    p_buffer_size = req.size;
 }
 
 static void ImGui_ImplVulkan_SetupRenderState(ImDrawData* draw_data, VkCommandBuffer command_buffer, ImGui_ImplVulkanH_FrameRenderBuffers* rb, int fb_width, int fb_height)
@@ -342,9 +342,9 @@ void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer comm
     {
         ImDrawVert* vtx_dst = NULL;
         ImDrawIdx* idx_dst = NULL;
-        err = vkMapMemory(v->Device, rb->VertexBufferMemory, 0, vertex_size, 0, (void**)(&vtx_dst));
+        err = vkMapMemory(v->Device, rb->VertexBufferMemory, 0, rb->VertexBufferSize, 0, (void**)(&vtx_dst));
         check_vk_result(err);
-        err = vkMapMemory(v->Device, rb->IndexBufferMemory, 0, index_size, 0, (void**)(&idx_dst));
+        err = vkMapMemory(v->Device, rb->IndexBufferMemory, 0, rb->IndexBufferSize, 0, (void**)(&idx_dst));
         check_vk_result(err);
         for (int n = 0; n < draw_data->CmdListsCount; n++)
         {