diff --git a/dmtree/tr181/dhcpv4.c b/dmtree/tr181/dhcpv4.c
index 41a4a76d..123d21c9 100644
--- a/dmtree/tr181/dhcpv4.c
+++ b/dmtree/tr181/dhcpv4.c
@@ -290,7 +290,7 @@ static void dhcp_leases_load(struct list_head *head)
 
 static int interface_get_ipv4(const char *iface, uint32_t *addr, unsigned *bits)
 {
-	json_object *res;
+	json_object *res = NULL;
 	const char *addr_str = NULL;
 	int addr_cidr = -1;
 
@@ -2114,7 +2114,7 @@ static int set_DHCPv4ClientSentOption_Value(char *refparam, struct dmctx *ctx, v
 			dmuci_set_value_by_section_bbfdm(dhcp_client_s->dmmap_sect, "option_value", res);
 
 			if (tag_enabled) {
-				char new_tag_value[128] = {0};
+				char new_tag_value[512] = {0};
 
 				snprintf(new_tag_value, sizeof(new_tag_value), "%s:%s", dhcp_client_s->option_tag, res);
 				add_elt_to_str_list(&sendopts, new_tag_value);
@@ -2452,7 +2452,7 @@ static int set_DHCPv4ServerPoolOption_Value(char *refparam, struct dmctx *ctx, v
 			convert_hex_to_string(value, res);
 
 			if (option_enabled) {
-				char new_tag_value[128] = {0}, old_tag_value[128] = {0};
+				char new_tag_value[512] = {0}, old_tag_value[128] = {0};
 
 				snprintf(old_tag_value, sizeof(old_tag_value), "%s,%s", dhcp_client_s->option_tag, dhcp_client_s->value);
 				snprintf(new_tag_value, sizeof(new_tag_value), "%s,%s", dhcp_client_s->option_tag, res);
diff --git a/dmtree/tr181/dhcpv6.c b/dmtree/tr181/dhcpv6.c
index 19d3bd7e..fb0aa502 100644
--- a/dmtree/tr181/dhcpv6.c
+++ b/dmtree/tr181/dhcpv6.c
@@ -1286,7 +1286,7 @@ static int set_DHCPv6ServerPoolOption_Value(char *refparam, struct dmctx *ctx, v
 			convert_hex_to_string(value, res);
 
 			if (option_enabled) {
-				char new_tag_value[128] = {0}, old_tag_value[128] = {0};
+				char new_tag_value[512] = {0}, old_tag_value[128] = {0};
 
 				snprintf(old_tag_value, sizeof(old_tag_value), "%s,%s", dhcpv6_client_s->option_tag, dhcpv6_client_s->value);
 				snprintf(new_tag_value, sizeof(new_tag_value), "%s,%s", dhcpv6_client_s->option_tag, res);
diff --git a/dmtree/tr181/dns.c b/dmtree/tr181/dns.c
index a34aeab1..2b9f36ab 100644
--- a/dmtree/tr181/dns.c
+++ b/dmtree/tr181/dns.c
@@ -30,7 +30,7 @@ static unsigned char is_dns_server_in_dmmap(char *chk_ip, char *chk_interface)
 
 static int dmmap_synchronizeDNSClientRelayServer(struct dmctx *dmctx, DMNODE *parent_node, void *prev_data, char *prev_instance)
 {
-	json_object *jobj, *arrobj = NULL;
+	json_object *jobj = NULL, *arrobj = NULL;
 	struct uci_list *v;
 	struct uci_element *e = NULL;
 	struct uci_section *s = NULL, *sdns = NULL, *stmp = NULL, *ss;
diff --git a/dmtree/tr181/dsl.c b/dmtree/tr181/dsl.c
index 5c2f77ef..fe54cc7f 100644
--- a/dmtree/tr181/dsl.c
+++ b/dmtree/tr181/dsl.c
@@ -169,7 +169,7 @@ static int browseDSLChannelInst(struct dmctx *dmctx, DMNODE *parent_node, void *
 ***************************************************************************/
 static char *get_dsl_value_without_argument(char *command1, char *id, char *command2, char *key)
 {
-	json_object *res;
+	json_object *res = NULL;
 	char command[16], *value = "0";
 
 	snprintf(command, sizeof(command), "%s.%s", command1, id);
@@ -181,7 +181,7 @@ static char *get_dsl_value_without_argument(char *command1, char *id, char *comm
 
 static char *get_dsl_value_without_argument_and_with_two_key(char *command1, char *id, char *command2, char *key1, char *key2)
 {
-	json_object *res;
+	json_object *res = NULL;
 	char command[16], *value = "0";
 
 	snprintf(command, sizeof(command), "%s.%s", command1, id);
@@ -193,7 +193,7 @@ static char *get_dsl_value_without_argument_and_with_two_key(char *command1, cha
 
 char *get_value_with_argument(char *command1, char *id, char *command2, char *argument, char *key)
 {
-	json_object *res;
+	json_object *res = NULL;
 	char command[16], *value = "0";
 
 	snprintf(command, sizeof(command), "%s.%s", command1, id);
@@ -205,7 +205,7 @@ char *get_value_with_argument(char *command1, char *id, char *command2, char *ar
 
 static char *get_dsl_value_array_without_argument(char *command1, char *id, char *command2, char *key)
 {
-	json_object *res;
+	json_object *res = NULL;
 	char command[16], *value= "0";
 
 	snprintf(command, sizeof(command), "%s.%s", command1, id);
diff --git a/dmtree/tr181/fast.c b/dmtree/tr181/fast.c
index a9b8ae4e..37b6def4 100644
--- a/dmtree/tr181/fast.c
+++ b/dmtree/tr181/fast.c
@@ -97,7 +97,7 @@ static int browseFASTLineInst(struct dmctx *dmctx, DMNODE *parent_node, void *pr
 ***************************************************************************/
 static char *get_fast_value_without_argument(char *command1, char *id, char *command2, char *key)
 {
-	json_object *res;
+	json_object *res = NULL;
 	char command[16], *value = "0";
 
 	snprintf(command, sizeof(command), "%s.%s", command1, id);
@@ -109,7 +109,7 @@ static char *get_fast_value_without_argument(char *command1, char *id, char *com
 
 static char *get_fast_value_without_argument_and_with_two_key(char *command1, char *id, char *command2, char *key1, char *key2)
 {
-	json_object *res;
+	json_object *res = NULL;
 	char command[16], *value = "0";
 
 	snprintf(command, sizeof(command), "%s.%s", command1, id);
@@ -121,7 +121,7 @@ static char *get_fast_value_without_argument_and_with_two_key(char *command1, ch
 
 static char *get_fast_value_array_without_argument(char *command1, char *id, char *command2, char *key)
 {
-	json_object *res;
+	json_object *res = NULL;
 	char command[16], *value= "0";
 
 	snprintf(command, sizeof(command), "%s.%s", command1, id);
diff --git a/dmtree/tr181/upnp.c b/dmtree/tr181/upnp.c
index 18e550e6..1acec34c 100644
--- a/dmtree/tr181/upnp.c
+++ b/dmtree/tr181/upnp.c
@@ -463,7 +463,7 @@ static int get_UPnPDiscovery_RootDeviceNumberOfEntries(char *refparam, struct dm
 
 static int get_UPnPDiscovery_DeviceNumberOfEntries(char *refparam, struct dmctx *ctx, void *data, char *instance, char **value)
 {
-	json_object *res,  *devices;
+	json_object *res = NULL,  *devices;
 
 	*value = "0";
 	dmubus_call("upnpc", "discovery", UBUS_ARGS{{}}, 0, &res);
@@ -481,7 +481,7 @@ static int get_UPnPDiscovery_DeviceNumberOfEntries(char *refparam, struct dmctx
 
 static int get_UPnPDiscovery_ServiceNumberOfEntries(char *refparam, struct dmctx *ctx, void *data, char *instance, char **value)
 {
-	json_object *res, *services;
+	json_object *res = NULL, *services;
 
 	*value = "0";
 	dmubus_call("upnpc", "discovery", UBUS_ARGS{{}}, 0, &res);
@@ -565,7 +565,7 @@ static int get_UPnPDiscoveryService_ParentDevice(char *refparam, struct dmctx *c
 
 static int get_UPnPDescription_DeviceDescriptionNumberOfEntries(char *refparam, struct dmctx *ctx, void *data, char *instance, char **value)
 {
-	json_object *res,  *descriptions;
+	json_object *res = NULL,  *descriptions;
 
 	*value = "0";
 	dmubus_call("upnpc", "description", UBUS_ARGS{{}}, 0, &res);
@@ -583,7 +583,7 @@ static int get_UPnPDescription_DeviceDescriptionNumberOfEntries(char *refparam,
 
 static int get_UPnPDescription_DeviceInstanceNumberOfEntries(char *refparam, struct dmctx *ctx, void *data, char *instance, char **value)
 {
-	json_object *res, *devicesinstances;
+	json_object *res = NULL, *devicesinstances;
 
 	*value = "0";
 	dmubus_call("upnpc", "description", UBUS_ARGS{{}}, 0, &res);
@@ -601,7 +601,7 @@ static int get_UPnPDescription_DeviceInstanceNumberOfEntries(char *refparam, str
 
 static int get_UPnPDescription_ServiceInstanceNumberOfEntries(char *refparam, struct dmctx *ctx, void *data, char *instance, char **value)
 {
-	json_object *res, *servicesinstances;
+	json_object *res = NULL, *servicesinstances;
 
 	*value = "0";
 	dmubus_call("upnpc", "description", UBUS_ARGS{{}}, 0, &res);
diff --git a/dmtree/tr181/usb.c b/dmtree/tr181/usb.c
index 90a48fde..8df85c85 100644
--- a/dmtree/tr181/usb.c
+++ b/dmtree/tr181/usb.c
@@ -788,7 +788,7 @@ static int get_USBUSBHostsHost_Type(char *refparam, struct dmctx *ctx, void *dat
 
 static int get_USBUSBHostsHost_PowerManagementEnable(char *refparam, struct dmctx *ctx, void *data, char *instance, char **value)
 {
-	char power[64];
+	char power[64] = {0};
 
 	__read_sysfs_usb_port(data, "power/level", power, sizeof(power));
 
@@ -1018,7 +1018,7 @@ static int get_USBUSBHostsHostDevice_MaxChildren(char *refparam, struct dmctx *c
 
 static int get_USBUSBHostsHostDevice_IsSuspended(char *refparam, struct dmctx *ctx, void *data, char *instance, char **value)
 {
-	char status[16];
+	char status[16] = {0};
 
 	__read_sysfs_usb_port(data, "power/runtime_status", status, sizeof(status));
 	if(strncmp(status, "suspended", 9) == 0)