diff --git a/gnu/build/activation.scm b/gnu/build/activation.scm
index 4b67926e88..83586ce16c 100644
--- a/gnu/build/activation.scm
+++ b/gnu/build/activation.scm
@@ -234,7 +234,7 @@ they already exist."
                                  "/" (basename prog))))
       (copy-file prog target)
       (chown target 0 0)
-      (chmod target #o6555)))
+      (chmod target #o4555)))
 
   (format #t "setting up setuid programs in '~a'...~%"
           %setuid-directory)