diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index d1f00706d41e..4e4af6e17b50 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -1021,8 +1021,9 @@ static inline bool mt76_is_skb_pktid(u8 pktid)
 static inline u8 mt76_tx_power_nss_delta(u8 nss)
 {
 	static const u8 nss_delta[4] = { 0, 6, 9, 12 };
+	u8 idx = nss - 1;
 
-	return nss_delta[nss - 1];
+	return (idx < ARRAY_SIZE(nss_delta)) ? nss_delta[idx] : 0;
 }
 
 static inline bool mt76_testmode_enabled(struct mt76_phy *phy)