The WNM Sleep Mode code in wpa_supplicant 2.x before 2.6 does not properly ignore key data in response frames when management frame protection (MFP) was not negotiated, which allows remote attackers to inject arbitrary broadcast or multicast packets or cause a denial of service (ignored packets) via a WNM Sleep Mode response.
w1.fi/security/2015-6/wpa_supplicant-unauthorized-wnm-sleep-mode-gtk-control.txt
www.debian.org/security/2015/dsa-3397
www.openwall.com/lists/oss-security/2015/11/10/9
www.securityfocus.com/bid/77541
www.securitytracker.com/id/1034592
www.ubuntu.com/usn/USN-2808-1
source.android.com/security/bulletin/2016-01-01.html