Zend Framework, as used in ownCloud Server before 5.0.15 and 6.0.x before 6.0.2, allows remote attackers to read arbitrary files, cause a denial of service, or possibly have other impact via an XML External Entity (XXE) attack.
https://www.securityfocus.com/bid/66222
https://owncloud.org/security/advisories/xxe-multiple-third-party-components/
http://owncloud.org/about/security/advisories/oC-SA-2014-006/