diff --git a/rtc_base/buffer.h b/rtc_base/buffer.h
index 3048b91..d1639e2 100644
--- a/rtc_base/buffer.h
+++ b/rtc_base/buffer.h
@@ -370,7 +370,9 @@
                        : capacity;
 
     std::unique_ptr<T[]> new_data(new T[new_capacity]);
-    std::memcpy(new_data.get(), data_.get(), size_ * sizeof(T));
+    if (data_ != nullptr) {
+      std::memcpy(new_data.get(), data_.get(), size_ * sizeof(T));
+    }
     MaybeZeroCompleteBuffer();
     data_ = std::move(new_data);
     capacity_ = new_capacity;