diff --git a/apps/server/src/api-data/db/db.validation.ts b/apps/server/src/api-data/db/db.validation.ts
index e864bd937..c04a48d7b 100644
--- a/apps/server/src/api-data/db/db.validation.ts
+++ b/apps/server/src/api-data/db/db.validation.ts
@@ -133,7 +133,8 @@ export const validateFilenameParam = [
     .customSanitizer((input: string) => sanitize(input))
     .withMessage('Failed to sanitize the filename')
     .notEmpty()
-    .withMessage('Filename was empty or contained only invalid characters'),
+    .withMessage('Filename was empty or contained only invalid characters')
+    .customSanitizer((input: string) => ensureJsonExtension(input)),
 
   (req: Request, res: Response, next: NextFunction) => {
     const errors = validationResult(req);