diff --git a/src/entry/Maat_api.cpp b/src/entry/Maat_api.cpp
index c963634..82e3bb5 100644
--- a/src/entry/Maat_api.cpp
+++ b/src/entry/Maat_api.cpp
@@ -1352,7 +1352,14 @@ int Maat_stream_scan_digest(stream_para_t * stream_para, const char * data, int
 	GIE_result_t query_result[MAX_SCANNER_HIT_NUM];
 	int hit_region_cnt=0,compile_ret=0;
 	_compile_result_t compile_result[rule_num];//dynamic array
-	//TODO: scanner ==NULL
+	if(data==NULL||data_len<=0)
+	{
+		return 0;
+	}
+	if(sp->feather->scanner==NULL)
+	{
+		return 0;
+	}
 	GIE_handle_t* GIE_handle=sp->feather->scanner->digest_handle[sp->table_id];
 	unsigned long long digest_len=0;
 	char* digest_buff=NULL;