CVE-2018-7644
The XmlSecLibs library as used in the saml2 library in SimpleSAMLphp before 1.15.3 incorrectly verifies signatures on SAML assertions, allowing a remote attacker construct a crafted SAML assertion on behalf of an Identity Provider that would pass as cryptographically valid, thereby allowing them to impersonate a user from that Identity Provider, aka a key confusion issue.
Source: CVE-2018-7644