diff --git a/app/Http/Controllers/Admin/PlatformOrderController.php b/app/Http/Controllers/Admin/PlatformOrderController.php
index b635d20..152ad44 100644
--- a/app/Http/Controllers/Admin/PlatformOrderController.php
+++ b/app/Http/Controllers/Admin/PlatformOrderController.php
@@ -8,6 +8,7 @@ use App\Models\Merchant;
 use App\Models\Plan;
 use App\Models\PlatformOrder;
 use App\Models\SiteSubscription;
+use App\Support\BackUrl;
 use App\Support\SubscriptionActivationService;
 use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Http\RedirectResponse;
@@ -47,12 +48,7 @@ class PlatformOrderController extends Controller
         // back 安全阀：必须为站内相对路径，并拒绝引号/尖括号。
         // 说明：form 页会把 defaults.back 透传到 hidden input 与返回按钮；因此这里提前清洗，避免 unsafe back 在页面中出现。
         $incomingBack = (string) ($defaults['back'] ?? '');
-        $defaults['back'] = (str_starts_with($incomingBack, '/')
-            && !preg_match('/["\'<>]/', $incomingBack)
-            // back 本身不应再包含 back（避免无限嵌套导致 URL 膨胀）
-            && !preg_match('/(?:^|[?&])back=/', $incomingBack))
-            ? $incomingBack
-            : '';
+        $defaults['back'] = BackUrl::sanitizeForLinks($incomingBack);
 
         $siteSubscription = null;
         $siteSubscriptionId = (int) ($defaults['site_subscription_id'] ?? 0);
@@ -153,13 +149,8 @@ class PlatformOrderController extends Controller
         }
 
         $back = (string) ($data['back'] ?? '');
-        // back 需为站内相对路径，并拒绝引号/尖括号，避免在后续页面以 `{!! !!}` 原样输出时引入 XSS 风险。
-        $safeBack = (str_starts_with($back, '/')
-            && !preg_match('/["\'<>]/', $back)
-            // back 本身不应再包含 back（避免无限嵌套导致 URL 膨胀）
-            && !preg_match('/(?:^|[?&])back=/', $back))
-            ? $back
-            : '';
+        // back 安全护栏：统一收敛到 BackUrl::sanitizeForLinks，避免口径漂移。
+        $safeBack = BackUrl::sanitizeForLinks($back);
 
         $redirectUrl = '/admin/platform-orders/' . $order->id;
         if ($safeBack !== '') {