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.
github.com/FriendsOfPHP/security-advisories/blob/master/simplesamlphp/simplesamlphp/CVE-2017-12872.yaml
github.com/simplesamlphp/simplesamlphp/commit/b72c79e3070f930d758f5c269333d63ed7509e2e
lists.debian.org/debian-lts-announce/2017/12/msg00007.html
lists.debian.org/debian-lts-announce/2018/06/msg00017.html
nvd.nist.gov/vuln/detail/CVE-2017-12872
simplesamlphp.org/security/201703-01