From 857b29009bdcf7e0ed8b8966bc831e12430c7698 Mon Sep 17 00:00:00 2001
From: Franco Fichtner <franco@opnsense.org>
Date: Fri, 18 Sep 2026 13:23:45 +0200
Subject: [PATCH] interfaces: retain empty fields also written by legacy GUI

---
 .../OPNsense/Interfaces/Api/AssignmentController.php     | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/opnsense/mvc/app/controllers/OPNsense/Interfaces/Api/AssignmentController.php b/src/opnsense/mvc/app/controllers/OPNsense/Interfaces/Api/AssignmentController.php
index 534d198c48..518f5eb7f0 100644
--- a/src/opnsense/mvc/app/controllers/OPNsense/Interfaces/Api/AssignmentController.php
+++ b/src/opnsense/mvc/app/controllers/OPNsense/Interfaces/Api/AssignmentController.php
@@ -159,6 +159,10 @@ class AssignmentController extends ApiMutableModelControllerBase
             'lock',
             'promisc',
         ];
+        $legacyempties = [
+            'descr',
+            'spoofmac',
+        ];
         if ($this->request->isPost()) {
             $backend = new Backend();
             /***
@@ -189,6 +193,11 @@ class AssignmentController extends ApiMutableModelControllerBase
                                 unset(Config::getInstance()->object()->interfaces->$key->$legacybool);
                             }
                         }
+                        foreach ($legacyempties as $legacyempty) {
+                            if (!strlen($pending[$legacyempty] ?? '')) {
+                                Config::getInstance()->object()->interfaces->$key->$legacyempty = '';
+                            }
+                        }
                         /* advanced dhcp settings not supported, prevent settings being used */
                         foreach (
                             [