diff --git a/common/crypto/auth.go b/common/crypto/auth.go
index 52c84ebc..41aeae11 100644
--- a/common/crypto/auth.go
+++ b/common/crypto/auth.go
@@ -245,6 +245,8 @@ func (w *AuthenticationWriter) Write(b []byte) (int, error) {
 }
 
 func (w *AuthenticationWriter) WriteMultiBuffer(mb buf.MultiBuffer) (int, error) {
+	defer mb.Release()
+
 	const StartIndex = 17 * 1024
 	var totalBytes int
 	for {
diff --git a/proxy/shadowsocks/protocol.go b/proxy/shadowsocks/protocol.go
index 993d7b62..daec7b61 100644
--- a/proxy/shadowsocks/protocol.go
+++ b/proxy/shadowsocks/protocol.go
@@ -385,6 +385,8 @@ type UDPWriter struct {
 }
 
 func (w *UDPWriter) Write(mb buf.MultiBuffer) error {
+	defer mb.Release()
+
 	for _, b := range mb {
 		if err := w.writeInternal(b); err != nil {
 			return err