diff -rup gtk-vnc-0.4.1.orig/src/vncconnection.c gtk-vnc-0.4.1.new/src/vncconnection.c
--- gtk-vnc-0.4.1.orig/src/vncconnection.c	2010-07-14 11:28:15.000000000 +0100
+++ gtk-vnc-0.4.1.new/src/vncconnection.c	2010-08-05 14:56:40.403911911 +0100
@@ -4191,7 +4191,10 @@ static void vnc_connection_close(VncConn
 		priv->name = NULL;
 	}
 
-	g_free (priv->xmit_buffer);
+	if (priv->xmit_buffer) {
+		g_free(priv->xmit_buffer);
+		priv->xmit_buffer = NULL;
+	}
 
 	if (priv->cred_username) {
 		g_free(priv->cred_username);