diff --git a/DirectXTex/d3dx12.h b/DirectXTex/d3dx12.h
index 57d79b8..6172287 100644
--- a/DirectXTex/d3dx12.h
+++ b/DirectXTex/d3dx12.h
@@ -2548,7 +2548,7 @@ inline HRESULT D3DX12ParsePipelineStream(const D3D12_PIPELINE_STATE_STREAM_DESC&
     {
         BYTE* pStream = static_cast<BYTE*>(Desc.pPipelineStateSubobjectStream)+CurOffset;
         auto SubobjectType = *reinterpret_cast<D3D12_PIPELINE_STATE_SUBOBJECT_TYPE*>(pStream);
-        if (SubobjectType >= D3D12_PIPELINE_STATE_SUBOBJECT_TYPE_MAX_VALID)
+        if (SubobjectType < 0 || SubobjectType >= D3D12_PIPELINE_STATE_SUBOBJECT_TYPE_MAX_VALID)
         {
             pCallbacks->ErrorUnknownSubobject(SubobjectType);
             return E_INVALIDARG;