xerces-c: denial of service

From the Gentoo advisory:

Frank Rast reported that the XML parser in Xerces-C++ does not correctly handle an XML schema definition with a large maxOccurs value, which triggers excessive memory consumption during the validation of an XML file.

A remote attacker could entice a user or automated system to validate an XML file using a specially crafted XML schema file, leading to a Denial of Service (stack consumption and crash).