diff --git a/src/SAFE.setting b/src/SAFE.setting
index e3e7f32f3de..24d75f9a063 100644
--- a/src/SAFE.setting
+++ b/src/SAFE.setting
@@ -7,6 +7,7 @@ sub unlink(|$) { restricted('unlink') }
 sub shell(|$)  { restricted('shell') }
 sub run(|$)    { restricted('run') }
 sub QX(|$)     { restricted('qx, qqx') }
+sub mkdir(|$)  { restricted('mkdir')   }
 
 my class IO { }
 IO.^add_fallback(