diff --git a/mt7996/mcu.c b/mt7996/mcu.c
index 1acdc212..a683ad86 100644
--- a/mt7996/mcu.c
+++ b/mt7996/mcu.c
@@ -2614,8 +2614,10 @@ int mt7996_mcu_add_key(struct mt76_dev *dev, struct ieee80211_vif *vif,
 		return PTR_ERR(skb);
 
 	ret = mt7996_mcu_sta_key_tlv(wcid, skb, key, cmd);
-	if (ret)
+	if (ret) {
+		dev_kfree_skb(skb);
 		return ret;
+	}
 
 	return mt76_mcu_skb_send_msg(dev, skb, mcu_cmd, true);
 }