diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 1ee2b1cfc756..3a1e2c9e1565 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -5275,7 +5275,8 @@ static void ieee80211_set_beacon_cntdwn(struct ieee80211_sub_if_data *sdata,
 		if (sdata->vif.type == NL80211_IFTYPE_AP && resp) {
 			u16 *resp_offsets = resp->cntdwn_counter_offsets;
 
-			resp->data[resp_offsets[i]] = count;
+			if (resp_offsets[i])
+				resp->data[resp_offsets[i]] = count;
 		}
 	}
 }