FreeCAD: XXE file read and SSRF via external entity injection in Document.xml SAX parser

FreeCAD is a free and open-source multiplatform 3D parametric modeler. Prior to 1.1.2, the Xerces SAX2 XMLReader constructed in src/Base/Reader.cpp by Base::XMLReader::XMLReader() parses attacker-controlled Document.xml from a crafted .FCStd archive without disabling default external entity resolution or external DTD loading. When Document::restore() opens the document, external entities can read local files through the file URI scheme or initiate server-side requests through the http URI scheme, and resolved content can flow through the characters() callback. This issue is fixed in version 1.1.2.