diff --git a/app/service/login_handlers/default.py b/app/service/login_handlers/default.py
index 1770194b4..804373f0c 100644
--- a/app/service/login_handlers/default.py
+++ b/app/service/login_handlers/default.py
@@ -57,7 +57,11 @@ async def _ldap_login(self, username, password):
         server = ldap3.Server(self._ldap_config.get('server'))
         dn = self._ldap_config.get('dn')
         user_attr = self._ldap_config.get('user_attr') or 'uid'
-        user_string = '%s=%s,%s' % (user_attr, username, dn)
+        user_format_string = self._ldap_config.get("user_format") or "{user_attr}={user},{dn}"
+        try:
+            user_string = user_format_string.format(user_attr=user_attr, user=username, dn=dn)
+        except KeyError:
+            user_string = '%s=%s,%s' % (user_attr, username, dn)
 
         try:
             with ldap3.Connection(server, user=user_string, password=password) as conn: