In Apache HTTP Server versions 2.4.0 to 2.4.23, malicious input to mod_auth_digest can cause the server to crash, and each instance continues to crash even for subsequently valid requests.
https://www.tenable.com/security/tns-2017-04
https://support.apple.com/HT208221
https://security.netapp.com/advisory/ntap-20180423-0001/
https://security.gentoo.org/glsa/201701-36
https://httpd.apache.org/security/vulnerabilities_24.html#CVE-2016-2161
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03725en_us
https://access.redhat.com/errata/RHSA-2017:1414
https://access.redhat.com/errata/RHSA-2017:1413
https://access.redhat.com/errata/RHSA-2017:1161
https://access.redhat.com/errata/RHSA-2017:0906
http://www.securitytracker.com/id/1037508
http://www.securityfocus.com/bid/95076