The SAML2 library before 1.10.4, 2.x before 2.3.5, and 3.x before 3.1.1 in SimpleSAMLphp has a Regular Expression Denial of Service vulnerability for fraction-of-seconds data in a timestamp.
Debian Linux Security Advisory 4127-1 - Several vulnerabilities have been discovered in SimpleSAMLphp, a framework for authentication, primarily via the SAML protocol.