diff --git a/tests/sys/acl/run b/tests/sys/acl/run
index 383f47e62397..40be88f2de29 100644
--- a/tests/sys/acl/run
+++ b/tests/sys/acl/run
@@ -70,7 +70,7 @@ for (;;) {
   if (defined $line) {
     # Substitute %VAR and %{VAR} with environment variables.
     $line =~ s[%(\w+)][$ENV{$1}]eg;
-    $line =~ s[%{(\w+)}][$ENV{$1}]eg;
+    $line =~ s[%\{(\w+)\}][$ENV{$1}]eg;
   }
   if (defined $line) {
     if ($line =~ s/^\s*< ?//) {