diff --git a/common/sniff/bittorrent.go b/common/sniff/bittorrent.go
index 9fa7d8b8..39c19598 100644
--- a/common/sniff/bittorrent.go
+++ b/common/sniff/bittorrent.go
@@ -68,7 +68,9 @@ func UTP(_ context.Context, metadata *adapter.InboundContext, packet []byte) err
 		if err != nil {
 			return err
 		}
-
+		if extension > 0x04 {
+			return os.ErrInvalid
+		}
 		var length byte
 		err = binary.Read(reader, binary.BigEndian, &length)
 		if err != nil {
diff --git a/common/sniff/bittorrent_test.go b/common/sniff/bittorrent_test.go
index 65f095bd..f4762e32 100644
--- a/common/sniff/bittorrent_test.go
+++ b/common/sniff/bittorrent_test.go
@@ -71,3 +71,19 @@ func TestSniffUDPTracker(t *testing.T) {
 		require.Equal(t, C.ProtocolBitTorrent, metadata.Protocol)
 	}
 }
+
+func TestSniffNotUTP(t *testing.T) {
+	t.Parallel()
+
+	packets := []string{
+		"0102736470696e674958d580121500000000000079aaed6717a39c27b07c0c000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+	}
+	for _, pkt := range packets {
+		pkt, err := hex.DecodeString(pkt)
+		require.NoError(t, err)
+
+		var metadata adapter.InboundContext
+		err = sniff.UTP(context.TODO(), &metadata, pkt)
+		require.Error(t, err)
+	}
+}