The (1) Htpasswd authentication source in the authcrypt module and (2) SimpleSAML_Session class in SimpleSAMLphp 1.14.11 and earlier allow remote attackers to conduct timing side-channel attacks by leveraging use of the standard comparison operator to compare secret material against user input.
https://simplesamlphp.org/security/201703-01
https://lists.debian.org/debian-lts-announce/2018/06/msg00017.html
https://lists.debian.org/debian-lts-announce/2017/12/msg00007.html