Shibboleth OpenSAML library 2.4.x before 2.4.3 and 2.5.x before 2.5.1, and IdP before 2.3.2, allows remote attackers to forge messages and bypass authentication via an "XML Signature wrapping attack."
http://www.oracle.com/technetwork/topics/security/cpuoct2012-1515893.html
http://www.mandriva.com/security/advisories?name=MDVSA-2013:150
http://www.debian.org/security/2011/dsa-2284