diff --git a/gst/isomp4/gstqtmux.c b/gst/isomp4/gstqtmux.c
index b339041..08aa05c 100644
--- a/gst/isomp4/gstqtmux.c
+++ b/gst/isomp4/gstqtmux.c
@@ -1414,6 +1414,7 @@
   {
     GST_ELEMENT_ERROR (qtmux, STREAM, MUX, (NULL),
         ("Failed to serialize mdat"));
+    g_free (node_header);
     return GST_FLOW_ERROR;
   }
 }