The WPS UPnP function in hostapd, when using WPS AP, and wpa_supplicant, when using WPS external registrar (ER), 0.7.0 through 2.4 allows remote attackers to cause a denial of service (crash) via a negative chunk length, which triggers an out-of-bounds read or heap-based buffer overflow.
lists.opensuse.org/opensuse-updates/2015-06/msg00019.html
w1.fi/security/2015-2/wps-upnp-http-chunked-transfer-encoding.txt
www.debian.org/security/2015/dsa-3397
www.openwall.com/lists/oss-security/2015/05/09/4
www.openwall.com/lists/oss-security/2015/05/31/6
www.ubuntu.com/usn/USN-2650-1
security.gentoo.org/glsa/201606-17