diff --git a/tools/core/flow.h b/tools/core/flow.h
index 43b59eb6..562f5384 100644
--- a/tools/core/flow.h
+++ b/tools/core/flow.h
@@ -192,6 +192,11 @@ class Flow {
       return IndexError_ReadData;
     }
 
+    if (!data_ptr) {
+      LOG_ERROR("Invalid data pointer for tag list header");
+      return IndexError_ReadData;
+    }
+
     memcpy(&taglist_header, data_ptr, sizeof(TagListHeader));
 
     auto segment_taglist_key = storage->get(TAGLIST_KEY_SEGMENT_NAME);
@@ -209,6 +214,11 @@ class Flow {
         return IndexError_ReadData;
       }
 
+      if (!data_ptr) {
+        LOG_ERROR("Invalid data pointer for tag list key");
+        return IndexError_ReadData;
+      }
+
       uint64_t key = *reinterpret_cast<const uint64_t *>(data_ptr);
       tag_key_list_.push_back(key);
 
@@ -231,6 +241,11 @@ class Flow {
         return IndexError_ReadData;
       }
 
+      if (!data_ptr) {
+        LOG_ERROR("Invalid data pointer for tag list offset");
+        return IndexError_ReadData;
+      }
+
       uint64_t tag_offset = *reinterpret_cast<const uint64_t *>(data_ptr);
       taglist_offsets.push_back(tag_offset);
 
@@ -246,6 +261,11 @@ class Flow {
       }
       offset += sizeof(uint64_t);
 
+      if (!data_ptr) {
+        LOG_ERROR("Invalid data pointer for tag count");
+        return IndexError_ReadData;
+      }
+
       uint64_t tag_count = *reinterpret_cast<const uint64_t *>(data_ptr);
 
       if (segment_taglist_data->read(offset, (const void **)(&data_ptr),
diff --git a/tools/core/helper.h b/tools/core/helper.h
index 037958e5..1fa916a4 100644
--- a/tools/core/helper.h
+++ b/tools/core/helper.h
@@ -221,6 +221,11 @@ int load_taglists(const std::string &path,
     return IndexError_ReadData;
   }
 
+  if (!data_ptr) {
+    LOG_ERROR("Invalid data pointer for tag list header");
+    return IndexError_ReadData;
+  }
+
   memcpy(&taglist_header, data_ptr, sizeof(TagListHeader));
 
   auto segment_taglist_key = storage->get(TAGLIST_KEY_SEGMENT_NAME);
@@ -238,6 +243,11 @@ int load_taglists(const std::string &path,
       return IndexError_ReadData;
     }
 
+    if (!data_ptr) {
+      LOG_ERROR("Invalid data pointer for tag list key");
+      return IndexError_ReadData;
+    }
+
     uint64_t key = *reinterpret_cast<const uint64_t *>(data_ptr);
     tag_key_list.push_back(key);
 
@@ -260,6 +270,11 @@ int load_taglists(const std::string &path,
       return IndexError_ReadData;
     }
 
+    if (!data_ptr) {
+      LOG_ERROR("Invalid data pointer for tag list offset");
+      return IndexError_ReadData;
+    }
+
     uint64_t tag_offset = *reinterpret_cast<const uint64_t *>(data_ptr);
     taglist_offsets.push_back(tag_offset);
 
@@ -275,6 +290,11 @@ int load_taglists(const std::string &path,
     }
     offset += sizeof(uint64_t);
 
+    if (!data_ptr) {
+      LOG_ERROR("Invalid data pointer for tag count");
+      return IndexError_ReadData;
+    }
+
     uint64_t tag_count = *reinterpret_cast<const uint64_t *>(data_ptr);
 
     if (segment_taglist_data->read(offset, (const void **)(&data_ptr),