diff --git a/dictionaries/ImpureFunctionsList.php b/dictionaries/ImpureFunctionsList.php
index d3a3f7ce0a3..25f94ef5298 100644
--- a/dictionaries/ImpureFunctionsList.php
+++ b/dictionaries/ImpureFunctionsList.php
@@ -85,6 +85,7 @@
     'ob_end_clean' => true,
     'ob_get_clean' => true,
     'readfile' => true,
+    'readgzfile' => true,
     'printf' => true,
     'var_dump' => true,
     'phpinfo' => true,