diff --git a/plugins/header_rewrite/operator.h b/plugins/header_rewrite/operator.h
index 7c2b6bdfe7d..6157900293e 100644
--- a/plugins/header_rewrite/operator.h
+++ b/plugins/header_rewrite/operator.h
@@ -85,7 +85,7 @@ class OperatorHeaders : public Operator
 
 protected:
   std::string _header;
-  const char *_header_wks;
+  const char *_header_wks = nullptr;
 };
 
 ///////////////////////////////////////////////////////////////////////////////