diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c
index 05c9c07591fc..6ca31d4ea437 100644
--- a/drivers/net/wireless/ath/ath5k/base.c
+++ b/drivers/net/wireless/ath/ath5k/base.c
@@ -1738,7 +1738,8 @@ ath5k_tx_frame_completed(struct ath5k_hw *ah, struct sk_buff *skb,
 	}
 
 	info->status.rates[ts->ts_final_idx].count = ts->ts_final_retry;
-	info->status.rates[ts->ts_final_idx + 1].idx = -1;
+	if (ts->ts_final_idx + 1 < IEEE80211_TX_MAX_RATES)
+		info->status.rates[ts->ts_final_idx + 1].idx = -1;
 
 	if (unlikely(ts->ts_status)) {
 		ah->stats.ack_fail++;