diff --git a/src/security/transform/buffer-source.hpp b/src/security/transform/buffer-source.hpp
index 0833a0f..c091d98 100644
--- a/src/security/transform/buffer-source.hpp
+++ b/src/security/transform/buffer-source.hpp
@@ -62,7 +62,7 @@
   /**
    * @brief Write the whole buffer into the next module.
    */
-  virtual void
+  void
   doPump() final;
 
 private: