Stack-based buffer overflow in the brcmf_cfg80211_start_ap function in drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c in the Linux kernel before 4.7.5 allows local users to cause a denial of service (system crash) or possibly have unspecified other impact via a long SSID Information Element in a command to a Netlink socket.