diff --git a/plugin/business/pangu-http/src/pangu_http.cpp b/plugin/business/pangu-http/src/pangu_http.cpp
index 0dc6809..3f318c1 100644
--- a/plugin/business/pangu-http/src/pangu_http.cpp
+++ b/plugin/business/pangu-http/src/pangu_http.cpp
@@ -1006,7 +1006,8 @@ void http_repl_ctx_free(struct replace_ctx* rep_ctx)
 
 void http_ins_ctx_free(struct insert_ctx* ins_ctx)
 {
-	FREE(&ins_ctx->rule->script);
+	if (ins_ctx->rule->script)
+		FREE(&ins_ctx->rule->script);
 	FREE(&ins_ctx->rule->type);
 	if (ins_ctx->rule->position)
 		FREE(&ins_ctx->rule->position);
@@ -1404,7 +1405,8 @@ void http_replace(const struct tfe_stream * stream, const struct tfe_http_sessio
 		rewrite_buff = NULL;
 		rewrite_sz = 0;
 
-		if (in_resp_spec->content_type != NULL && strstr(in_resp_spec->content_type, "charset=utf-8"))
+		if (in_resp_spec != NULL && in_resp_spec->content_type != NULL
+			&& strstr(in_resp_spec->content_type, "charset=utf-8"))
 		{
 			options = 1;
 		}
@@ -1831,6 +1833,7 @@ enum pangu_action http_scan(const struct tfe_http_session * session, enum tfe_ht
 	void * iterator = NULL;
 	const char * field_val = NULL;
 	struct http_field_name field_name;
+	struct tfe_http_half * http_half;
 	struct Maat_rule_t result[MAX_SCAN_RESULT];
 	char buff[TFE_STRING_MAX], * p = NULL;
 	int scan_ret = 0, table_id = 0;
@@ -1854,9 +1857,10 @@ enum pangu_action http_scan(const struct tfe_http_session * session, enum tfe_ht
 	{
 		table_id = events & EV_HTTP_REQ_HDR ? g_pangu_rt->scan_table_id[PXY_CTRL_HTTP_REQ_HDR] : g_pangu_rt
 			->scan_table_id[PXY_CTRL_HTTP_RES_HDR];
+		http_half = events & EV_HTTP_REQ_HDR ? session->req : session->resp;
 		while (hit_cnt < MAX_SCAN_RESULT)
 		{
-			field_val = tfe_http_field_iterate(session->req, &iterator, &field_name);
+			field_val = tfe_http_field_iterate(http_half, &iterator, &field_name);
 			if (field_val == NULL)
 			{
 				break;
diff --git a/plugin/business/pangu-http/src/pattern_replace.cpp b/plugin/business/pangu-http/src/pattern_replace.cpp
index c5a5f4b..086970c 100644
--- a/plugin/business/pangu-http/src/pattern_replace.cpp
+++ b/plugin/business/pangu-http/src/pattern_replace.cpp
@@ -321,6 +321,11 @@ size_t insert_string(char * in, size_t in_sz, const char *insert_on, const char
 	char* insert_from=NULL;
 	size_t offset=0;
 
+	if (script == NULL)
+	{
+		return 0;
+	}
+
 	if (insert_on != NULL && 0==strcasecmp(insert_on, "after-page-load"))
 	{
 		insert_from=strstr(in, "</body>");