Уязвимость функции xmlSchemaFixupComplexType (xmlschemas.c) библиотеки Libxml2, позволяющая нарушителю вызвать отказ в обслуживании

Уязвимость функции xmlDictComputeFastKey (dict.c) библиотеки Libxml2, позволяющая нарушителю вызвать отказ в обслуживании

In libxml2 before 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.

An issue was discovered in libxml2 before 2.10.4. When hashing empty dict strings in a crafted XML document, xmlDictComputeFastKey in dict.c can produce non-deterministic values, leading to various logic and memory errors, such as a double free. This behavior occurs because there is an attempt to use the first byte of an empty string, and any value is possible (not solely the '\0' value).