diff --git a/src/etc/inc/interfaces.lib.inc b/src/etc/inc/interfaces.lib.inc
index 407ac7a04..627361b8b 100644
--- a/src/etc/inc/interfaces.lib.inc
+++ b/src/etc/inc/interfaces.lib.inc
@@ -360,7 +360,7 @@ function legacy_interfaces_details($intf = null)
             if (empty($result[$current_interface]["carp"])) {
                 $result[$current_interface]["carp"] = array();
             }
-            $result[$current_interface]["carp"][] = array(
+            $result[$current_interface]["carp"][$line_parts[3]] = array(
                 "status" => $line_parts[1],
                 "vhid" => $line_parts[3],
                 "advbase" => $line_parts[5],