diff --git a/tree.c b/tree.c
index c1452a48..eae778d6 100644
--- a/tree.c
+++ b/tree.c
@@ -4090,6 +4090,10 @@ xmlCopyNamespaceList(xmlNsPtr cur) {
 
     while (cur != NULL) {
         q = xmlCopyNamespace(cur);
+        if (q == NULL) {
+            xmlFreeNsList(ret);
+            return(NULL);
+        }
 	if (p == NULL) {
 	    ret = p = q;
 	} else {