CVE 2015-4141
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.
See the 
CVE page on Mitre.org
for more details.
