diff --git a/NEWS b/NEWS
index 5a69794db52a4..a0ea502c45a53 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,7 @@ PHP                                                                        NEWS
   . Fix empty argument cases for DOMParentNode methods. (nielsdos)
   . Fixed bug GH-11791 (Wrong default value of DOMDocument::xmlStandalone).
     (nielsdos)
+  . Fix json_encode result on DOMDocument. (nielsdos)
 
 - Core:
   . Fixed oss-fuzz #60741 (Leak in open_basedir). (ilutov)
diff --git a/ext/dom/php_dom.stub.php b/ext/dom/php_dom.stub.php
index 955721dd230c0..7316f8426698b 100644
--- a/ext/dom/php_dom.stub.php
+++ b/ext/dom/php_dom.stub.php
@@ -707,7 +707,7 @@ class DOMDocument extends DOMNode implements DOMParentNode
      * @readonly
      * @deprecated
      */
-    public mixed $config = null;
+    public mixed $config;
 
     public bool $formatOutput;
 
diff --git a/ext/dom/tests/DOMDocument_json_encode.phpt b/ext/dom/tests/DOMDocument_json_encode.phpt
new file mode 100644
index 0000000000000..ed85ab4f2109e
--- /dev/null
+++ b/ext/dom/tests/DOMDocument_json_encode.phpt
@@ -0,0 +1,11 @@
+--TEST--
+JSON encoding a DOMDocument
+--EXTENSIONS--
+dom
+--FILE--
+<?php
+$doc = new DOMDocument;
+echo json_encode($doc);
+?>
+--EXPECT--
+{}