diff --git a/apps/emqx_authn/src/simple_authn/emqx_authn_mongodb.erl b/apps/emqx_authn/src/simple_authn/emqx_authn_mongodb.erl
index 1faabf75d..f515a12e9 100644
--- a/apps/emqx_authn/src/simple_authn/emqx_authn_mongodb.erl
+++ b/apps/emqx_authn/src/simple_authn/emqx_authn_mongodb.erl
@@ -90,6 +90,10 @@ filter(type) ->
     map();
 filter(desc) ->
     ?DESC(?FUNCTION_NAME);
+filter(required) ->
+    false;
+filter(default) ->
+    #{};
 filter(_) ->
     undefined.
 
diff --git a/apps/emqx_authz/src/emqx_authz_api_schema.erl b/apps/emqx_authz/src/emqx_authz_api_schema.erl
index bed953dbb..ff015cee2 100644
--- a/apps/emqx_authz/src/emqx_authz_api_schema.erl
+++ b/apps/emqx_authz/src/emqx_authz_api_schema.erl
@@ -193,6 +193,10 @@ filter(type) ->
     map();
 filter(desc) ->
     ?DESC(?FUNCTION_NAME);
+filter(required) ->
+    false;
+filter(default) ->
+    #{};
 filter(_) ->
     undefined.
 
diff --git a/apps/emqx_authz/src/emqx_authz_schema.erl b/apps/emqx_authz/src/emqx_authz_schema.erl
index 089afba4d..d5cb86a9f 100644
--- a/apps/emqx_authz/src/emqx_authz_schema.erl
+++ b/apps/emqx_authz/src/emqx_authz_schema.erl
@@ -279,7 +279,8 @@ mongo_common_fields() ->
         }},
         {filter, #{
             type => map(),
-            required => true,
+            required => false,
+            default => #{},
             desc => ?DESC(filter)
         }}
     ].