The XML parser in Xerces-C++ before 3.0.0 allows context-dependent attackers to cause a denial of service (stack consumption and crash) via an XML schema definition with a large maxOccurs value, which triggers excessive memory consumption during validation of an XML file.
https://exchange.xforce.ibmcloud.com/vulnerabilities/45596
http://xerces.apache.org/xerces-c/releases.html