The resolver in nginx before 1.8.1 and 1.9.x before 1.9.10 does not properly limit CNAME resolution, which allows remote attackers to cause a denial of service (worker process resource consumption) via vectors related to arbitrary name resolution.
lists.opensuse.org/opensuse-updates/2016-02/msg00042.html
mailman.nginx.org/pipermail/nginx/2016-January/049700.html
seclists.org/fulldisclosure/2021/Sep/36
www.debian.org/security/2016/dsa-3473
www.securitytracker.com/id/1034869
www.ubuntu.com/usn/USN-2892-1
access.redhat.com/errata/RHSA-2016:1425
bto.bluecoat.com/security-advisory/sa115
bugzilla.redhat.com/show_bug.cgi?id=1302589
security.gentoo.org/glsa/201606-06
support.apple.com/kb/HT212818