IssueDescription:

It was found that the ParserPool and Decrypter classes in the OpenSAML Java implementation resolved external entities, permitting XML External Entity (XXE) attacks. A remote attacker could use this flaw to read files accessible to the user running the application server, and potentially perform other more advanced XXE attacks.

The DynamicMetadataProvider class in saml/saml2/metadata/impl/DynamicMetadataProvider.cpp in OpenSAML-C in OpenSAML before 2.6.1 fails to properly configure itself with the MetadataFilter plugins and does not perform critical security checks such as signature verification, enforcement of validity periods, and other checks specific to deployments, aka CPPOST-105.