ouch a non-defined namespace could lead to a crash, fixed #61215 Daniel

* SAX.c: ouch a non-defined namespace could lead to a crash, fixed #61215
Daniel
diff --git a/SAX.c b/SAX.c
index 163ee9b..59158a2 100644
--- a/SAX.c
+++ b/SAX.c
@@ -1139,7 +1139,7 @@
      * set the namespace node, making sure that if the default namspace
      * is unbound on a parent we simply kee it NULL
      */
-    if ((ns != NULL) && (ns->href[0] != 0))
+    if ((ns != NULL) && (ns->href != NULL) && (ns->href[0] != 0))
 	xmlSetNs(ret, ns);
 
     /*