diff --git a/lib/web/desktop.go b/lib/web/desktop.go
index d475135fe9d77..60f062554688c 100644
--- a/lib/web/desktop.go
+++ b/lib/web/desktop.go
@@ -495,7 +495,7 @@ func proxyWebsocketConn(ws *websocket.Conn, wds net.Conn) error {
 	go func() {
 		defer closeOnce.Do(close)
 
-		buf := make([]byte, 4096)
+		var buf bytes.Buffer
 		for {
 			_, reader, err := ws.NextReader()
 			switch {
@@ -506,13 +506,13 @@ func proxyWebsocketConn(ws *websocket.Conn, wds net.Conn) error {
 				errs <- err
 				return
 			}
-			n, err := reader.Read(buf)
-			if err != nil {
+			buf.Reset()
+			if _, err := io.Copy(&buf, reader); err != nil {
 				errs <- err
 				return
 			}
 
-			if _, err := wds.Write(buf[:n]); err != nil {
+			if _, err := wds.Write(buf.Bytes()); err != nil {
 				errs <- trace.Wrap(err, "sending TDP message to desktop agent")
 				return
 			}