GHSA-F4G9-H89H-JGV9 SAML XML Signature wrapping in PySAML2

Impact All users of pysaml2 that use the default CryptoBackendXmlSec1 backend and need to verify signed SAML documents are impacted. pysaml2 = 6.4.1 does not validate the SAML document against an XML schema. This allows invalid XML documents to trick the verification process, by presenting elemen...