NULL Pointer Dereference
In libxml2 versions prior to 2.10.4, parsing of certain invalid XSD schemas can lead to a NULL Pointer Dereference and subsequently a segfault. This occurs in "xmlSchemaFixupComplexType" in "xmlschemas.c".
CWE-476 - NULL Pointer Dereference
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.