MaterialX's Lack of Import Depth Limit Leads to DoS (Denial-Of-Service) Via Stack Exhaustion

MaterialX is an open standard for the exchange of rich material and look-development content across applications and renderers. In version 1.39.2, nested imports of MaterialX files can lead to a crash via stack memory exhaustion, due to the lack of a limit on the "import chain" depth. When parsing file imports, recursion is used to process nested files; however, there is no limit imposed to the depth of files that can be parsed by the library. By building a sufficiently deep chain of MaterialX files one referencing the next, it is possible to crash the process using the MaterialX library via stack exhaustion. This is fixed in version 1.39.3.