diff --git a/ChangeLog b/ChangeLog
index 8b6f498..4b2b6d1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -332,6 +332,13 @@ Version 1.8.0
 Version 1.6.18
 *******************************************************************************
 
+2012-04-20 Yoichi NAKAYAMA <yoichi.nakayama(at)gmail.com>
+
+	Avoid dereference of null pointer in ixmlNode_setNodeProperties.
+
+	The problem can occur if one of the arguments is NULL.
+	Test argument and fix assertion.
+
 2012-04-17 Yoichi NAKAYAMA <yoichi.nakayama(at)gmail.com>
 
 	Create intermediate directory per project on vc9.
diff --git a/ixml/src/node.c b/ixml/src/node.c
index c20b841..1d1ec16 100644
--- a/ixml/src/node.c
+++ b/ixml/src/node.c
@@ -1339,7 +1339,10 @@ int ixmlNode_setNodeProperties(
 {
 	int rc;
 
-	assert(destNode != NULL || src != NULL);
+	assert(destNode != NULL && src != NULL);
+	if(destNode == NULL || src == NULL) {
+		return IXML_INVALID_PARAMETER;
+	}
 
 	rc = ixmlNode_setNodeValue(destNode, src->nodeValue);
 	if(rc != IXML_SUCCESS) {