The (1) BasicParserPool, (2) StaticBasicParserPool, (3) XML Decrypter, and (4) SAML Decrypter in Shibboleth OpenSAML-Java before 2.6.1 set the expandEntityReferences property to true, which allows remote attackers to conduct XML external entity (XXE) attacks via a crafted XML DOCTYPE declaration.
https://www.oracle.com/security-alerts/cpujan2022.html
https://bugzilla.redhat.com/show_bug.cgi?id=1043332
http://shibboleth.net/community/advisories/secadv_20131213.txt
http://rhn.redhat.com/errata/RHSA-2014-0195.html
http://rhn.redhat.com/errata/RHSA-2014-0172.html
http://rhn.redhat.com/errata/RHSA-2014-0171.html
http://rhn.redhat.com/errata/RHSA-2014-0170.html
http://blog.sendsafely.com/post/69590974866/web-based-single-sign-on-and-the-dangers-of-saml-xml