The read_request_line function in server/protocol.c in the Apache HTTP Server 2.4.12 does not initialize the protocol structure member, which allows remote attackers to cause a denial of service (NULL pointer dereference and process crash) by sending a request that lacks a method to an installation that enables the INCLUDES filter and has an ErrorDocument 400 directive specifying a local URI.
https://support.apple.com/kb/HT205031
https://support.apple.com/HT205219
https://github.com/apache/httpd/commit/be0f5335e3e73eb63253b050fdc23f252f5c8ae3
https://github.com/apache/httpd/commit/6a974059190b8a0c7e499f4ab12fe108127099cb
https://bz.apache.org/bugzilla/show_bug.cgi?id=57531
http://www.securitytracker.com/id/1032967
http://www.securityfocus.com/bid/75964
http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
http://www.oracle.com/technetwork/topics/security/bulletinoct2015-2511968.html
http://www.apache.org/dist/httpd/CHANGES_2.4
http://rhn.redhat.com/errata/RHSA-2015-1666.html
http://lists.apple.com/archives/security-announce/2015/Sep/msg00004.html
http://lists.apple.com/archives/security-announce/2015/Aug/msg00001.html