diff --git a/miniserv.pl b/miniserv.pl
index 0b080e90f..2ed52e0d4 100755
--- a/miniserv.pl
+++ b/miniserv.pl
@@ -2458,7 +2458,8 @@ if (&get_type($full) eq "internal/cgi" && $validated != 4) {
 	$ENV{"ANONYMOUS_USER"} = "1" if ($validated == 3 || $validated == 4);
 	$ENV{"DOCUMENT_ROOT"} = $roots[0];
 	$ENV{"THEME_ROOT"} = "$roots[0]/" .
-	                     ($config{"preroot_$authuser"} ||
+	                     ($config{"preroot_$ENV{'BASE_REMOTE_USER'}"} ||
+	                      $config{"preroot_$ENV{'REMOTE_USER'}"} ||
 	                      $config{"preroot"});
 	$ENV{"DOCUMENT_REALROOT"} = $realroot;
 	$ENV{"GATEWAY_INTERFACE"} = "CGI/1.1";
@@ -6348,7 +6349,8 @@ if (!$pid) {
 	$ENV{"WEBMIN_CRON"} = 1;
 	$ENV{"DOCUMENT_ROOT"} = $root0;
 	$ENV{"THEME_ROOT"} = "$root0/" .
-	                     ($config{"preroot_$ENV{'REMOTE_USER'}"} ||
+	                     ($config{"preroot_$ENV{'BASE_REMOTE_USER'}"} ||
+	                      $config{"preroot_$ENV{'REMOTE_USER'}"} ||
 	                      $config{"preroot"});
 	$ENV{"DOCUMENT_REALROOT"} = $root0;
 	$ENV{"MINISERV_CONFIG"} = $config_file;