diff --git a/ext/dom/parentnode/tree.c b/ext/dom/parentnode/tree.c
index e3de2b9bfff..ef1ad42b68c 100644
--- a/ext/dom/parentnode/tree.c
+++ b/ext/dom/parentnode/tree.c
@@ -379,6 +379,11 @@ xmlNode* dom_zvals_to_single_node(php_libxml_ref_obj *document, xmlNode *context
 			newNodeObj = Z_DOMOBJ_P(&nodes[i]);
 			newNode = dom_object_get_node(newNodeObj);
 
+			if (UNEXPECTED(!newNode)) {
+				php_dom_throw_error(INVALID_STATE_ERR, /* strict */ true);
+				goto err;
+			}
+
 			if (!dom_is_pre_insert_valid_without_step_1(document, node, newNode, NULL, documentNode)) {
 				goto err;
 			}
diff --git a/ext/dom/tests/gh16039.phpt b/ext/dom/tests/gh16039.phpt
new file mode 100644
index 00000000000..48a862eda7b
--- /dev/null
+++ b/ext/dom/tests/gh16039.phpt
@@ -0,0 +1,31 @@
+--TEST--
+GH-16039 (Segmentation fault (access null pointer) in ext/dom/parentnode/tree.c)
+--EXTENSIONS--
+dom
+--FILE--
+<?php
+
+$dom = new DOMDocument;
+$element = $dom->appendChild($dom->createElement('root'));
+try {
+    $element->prepend('x', new DOMEntity);
+} catch (DOMException $e) {
+    echo $e->getMessage(), "\n";
+}
+echo $dom->saveXML();
+$dom->strictErrorChecking = false; // Should not have influence
+try {
+    $element->prepend('x', new DOMEntity);
+} catch (DOMException $e) {
+    echo $e->getMessage(), "\n";
+}
+echo $dom->saveXML();
+
+?>
+--EXPECT--
+Invalid State Error
+<?xml version="1.0"?>
+<root/>
+Invalid State Error
+<?xml version="1.0"?>
+<root/>