diff --git a/sources/form/formmanager.class.inc.php b/sources/form/formmanager.class.inc.php
index 4f20d1f4c..5b4c98fcf 100644
--- a/sources/form/formmanager.class.inc.php
+++ b/sources/form/formmanager.class.inc.php
@@ -21,6 +21,7 @@
 namespace Combodo\iTop\Form;
 
 use Combodo\iTop\Renderer\FormRenderer;
+use CoreException;
 
 /**
  * Description of formmanager
@@ -59,6 +60,12 @@ abstract class FormManager
 		$oFormManager = new static();
 
 		$sFormRendererClass = $aJson['formrenderer_class'];
+        // N°7455 - Ensure form renderer class extends FormRenderer
+        if (false === is_a($sFormRendererClass, self::class, true))
+        {
+            throw new CoreException('Form renderer class must extend '.self::class);
+        }
+
 		/** @var \Combodo\iTop\Renderer\FormRenderer $oFormRenderer */
 		$oFormRenderer = new $sFormRendererClass();
 		$oFormRenderer->SetEndpoint($aJson['formrenderer_endpoint']);