diff --git a/components/bootloader_support/src/bootloader_common.c b/components/bootloader_support/src/bootloader_common.c
index 98e5606ede..12f60e9ce1 100644
--- a/components/bootloader_support/src/bootloader_common.c
+++ b/components/bootloader_support/src/bootloader_common.c
@@ -134,7 +134,7 @@ bool bootloader_common_erase_part_type_data(const char *list_erase, bool ota_dat
                     fl_ota_data_erase = true;
                 }
                 // partition->label is not null-terminated string.
-                strncpy(label, (char *)&partition->label, sizeof(partition->label));
+                strncpy(label, (char *)&partition->label, sizeof(label) - 1);
                 if (fl_ota_data_erase == true || (bootloader_common_label_search(list_erase, label) == true)) {
                     err = esp_rom_spiflash_erase_area(partition->pos.offset, partition->pos.size);
                     if (err != ESP_OK) {
diff --git a/components/spi_flash/partition.c b/components/spi_flash/partition.c
index 4003291999..7f63d4c343 100644
--- a/components/spi_flash/partition.c
+++ b/components/spi_flash/partition.c
@@ -176,7 +176,7 @@ static esp_err_t load_partitions()
         }
 
         // it->label may not be zero-terminated
-        strncpy(item->info.label, (const char*) it->label, sizeof(it->label));
+        strncpy(item->info.label, (const char*) it->label, sizeof(item->info.label) - 1);
         item->info.label[sizeof(it->label)] = 0;
         // add it to the list
         if (last == NULL) {