diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 0d34cca387022bb89c7318ae94de1a99810ab8f8..b1df42e4f1eb9ad637e8190d243434430c28e102 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -229,9 +229,13 @@ static int validate_beacon_head(const struct nlattr *attr,
 	unsigned int len = nla_len(attr);
 	const struct element *elem;
 	const struct ieee80211_mgmt *mgmt = (void *)data;
-	bool s1g_bcn = ieee80211_is_s1g_beacon(mgmt->frame_control);
 	unsigned int fixedlen, hdrlen;
+	bool s1g_bcn;
 
+	if (len < offsetofend(typeof(*mgmt), frame_control))
+		goto err;
+
+	s1g_bcn = ieee80211_is_s1g_beacon(mgmt->frame_control);
 	if (s1g_bcn) {
 		fixedlen = offsetof(struct ieee80211_ext,
 				    u.s1g_beacon.variable);