diff --git a/epan/dissectors/packet-isakmp.c b/epan/dissectors/packet-isakmp.c
index 10defc90cb..a5b9e4fd78 100644
--- a/epan/dissectors/packet-isakmp.c
+++ b/epan/dissectors/packet-isakmp.c
@@ -2719,7 +2719,7 @@ dissect_config_attribute(tvbuff_t *tvb, proto_tree *cfg_attr_type_tree, int offs
 	guint optlen, cfg_attr_type, len = 0;
         int offset_end = 0;	
 	proto_item *cfg_attr_type_item;
-	proto_tree *sub_cfg_attr_type_tree;
+	proto_tree *sub_cfg_attr_type_tree = NULL;
 
 	cfg_attr_type = tvb_get_ntohs(tvb, offset);
 	optlen = tvb_get_ntohs(tvb, offset+2);