diff --git a/pkgs/build-support/buildenv/default.nix b/pkgs/build-support/buildenv/default.nix
index 41a1e67ef42..337963106b4 100644
--- a/pkgs/build-support/buildenv/default.nix
+++ b/pkgs/build-support/buildenv/default.nix
@@ -63,6 +63,7 @@ runCommand name
       priority = drv.meta.priority or 5;
     }) paths);
     preferLocalBuild = true;
+    allowSubstitutes = false;
     # XXX: The size is somewhat arbitrary
     passAsFile = if builtins.stringLength pkgs >= 128*1024 then [ "pkgs" ] else null;
   }