GHSA-7QW8-3VMF-GJ32 MaterialX Null Pointer Dereference in MaterialXCore Shader Generation due to Unchecked implGraphOutput

Summary When parsing shader nodes in a MTLX file, the MaterialXCore code accesses a potentially null pointer, which can lead to crashes with maliciously crafted files. Details In source/MaterialXCore/Material.cpp, the following code extracts the output nodes for a given implementation graph: cpp...