diff --git a/packages/core/src/helpers/getAttributesFromExtensions.ts b/packages/core/src/helpers/getAttributesFromExtensions.ts
index b8dedc56..65de01ad 100644
--- a/packages/core/src/helpers/getAttributesFromExtensions.ts
+++ b/packages/core/src/helpers/getAttributesFromExtensions.ts
@@ -93,7 +93,7 @@ export function getAttributesFromExtensions(extensions: Extensions): ExtensionAt
           ...attribute,
         }
 
-        if (attribute.isRequired && attribute.default === undefined) {
+        if (attribute?.isRequired && attribute?.default === undefined) {
           delete mergedAttr.default
         }