GHSA-3jhf-gxhr-q4cx MaterialX Null Pointer Dereference in getShaderNodes due to Unchecked nodeGraph->getOutput return

• PyPI MaterialX: >= 1.39.2, < 1.39.3 → fixed in 1.39.3

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 `src/MaterialXCore/Material.cpp`, in function `getShaderNodes`, the following code fetches the output nodes for a given `nodegraph` input node: ```cpp // SNIP... else if (input->hasNodeGraphString()) { // Check upstream nodegraph connected to the input. // If no explicit output name given then scan all outputs on the nodegraph. ElementPtr parent = materialNode->getParent(); NodeGraphPtr nodeGraph = parent->getChildOfType(input->getNodeGraphString()); if (!nodeGraph) { continue; } vector outputs; if (input->hasOutputString()) { outputs.push_back(nodeGraph->getOutput(input->getOutputString())); // getOutputs(); } for (OutputPtr output : outputs) { NodePtr upstreamNode = output->getConnectedNode(); // getNodeDef(target)) { continue; } shaderNodeVec.push_back(upstreamNode); shaderNodeSet.insert(upstreamNode); } } } } // SNIP... ``` The issues arise because the `nodeGraph->getOutput(input->getOutputString())` call can return a null pointer, therefore when trying to call `output->getConnectedNode()`, this results in a crash . PoC Please download `nullptr_getshadernodes.mltx` from the following link: https://github.com/ShielderSec/poc/tree/main/CVE-2025-53010 `build/bin/MaterialXView --material nullptr_getshadernodes.mtlx` Impact An attacker could intentionally crash a target program that uses OpenEXR by sending a malicious MTLX file.