diff --git a/ext/dom/node.c b/ext/dom/node.c
index 973505c5b01a9..82f40860cfd35 100644
--- a/ext/dom/node.c
+++ b/ext/dom/node.c
@@ -1614,7 +1614,7 @@ static void dom_canonicalization(INTERNAL_FUNCTION_PARAMETERS, int mode) /* {{{
 		zval *tmp;
 		char *xquery;
 
-		tmp = zend_hash_str_find(ht, "query", sizeof("query")-1);
+		tmp = zend_hash_str_find_deref(ht, "query", sizeof("query")-1);
 		if (!tmp) {
 			/* if mode == 0 then $xpath arg is 3, if mode == 1 then $xpath is 4 */
 			zend_argument_value_error(3 + mode, "must have a \"query\" key");
@@ -1630,12 +1630,13 @@ static void dom_canonicalization(INTERNAL_FUNCTION_PARAMETERS, int mode) /* {{{
 		ctxp = xmlXPathNewContext(docp);
 		ctxp->node = nodep;
 
-		tmp = zend_hash_str_find(ht, "namespaces", sizeof("namespaces")-1);
+		tmp = zend_hash_str_find_deref(ht, "namespaces", sizeof("namespaces")-1);
 		if (tmp && Z_TYPE_P(tmp) == IS_ARRAY && !HT_IS_PACKED(Z_ARRVAL_P(tmp))) {
 			zval *tmpns;
 			zend_string *prefix;
 
 			ZEND_HASH_MAP_FOREACH_STR_KEY_VAL(Z_ARRVAL_P(tmp), prefix, tmpns) {
+				ZVAL_DEREF(tmpns);
 				if (Z_TYPE_P(tmpns) == IS_STRING) {
 					if (prefix) {
 						xmlXPathRegisterNs(ctxp, (xmlChar *) ZSTR_VAL(prefix), (xmlChar *) Z_STRVAL_P(tmpns));
diff --git a/ext/dom/tests/DOMNode_C14N_references.phpt b/ext/dom/tests/DOMNode_C14N_references.phpt
new file mode 100644
index 0000000000000..514e22be6365a
--- /dev/null
+++ b/ext/dom/tests/DOMNode_C14N_references.phpt
@@ -0,0 +1,41 @@
+--TEST--
+Test: Canonicalization - C14N() with references
+--EXTENSIONS--
+dom
+--FILE--
+<?php
+// Adapted from canonicalization.phpt
+
+$xml = <<<EOXML
+<?xml version="1.0" encoding="ISO-8859-1" ?>
+<foo xmlns="http://www.example.com/ns/foo"
+     xmlns:fubar="http://www.example.com/ns/fubar" xmlns:test="urn::test"><contain>
+  <bar><test1 /></bar>
+  <bar><test2 /></bar>
+  <fubar:bar xmlns:fubar="http://www.example.com/ns/fubar"><test3 /></fubar:bar>
+  <fubar:bar><test4 /></fubar:bar>
+</contain>
+</foo>
+EOXML;
+
+$dom = new DOMDocument();
+$dom->loadXML($xml);
+$doc = $dom->documentElement->firstChild;
+
+$xpath = [
+    'query' => '(//a:contain | //a:bar | .//namespace::*)',
+    'namespaces' => ['a' => 'http://www.example.com/ns/foo'],
+];
+$prefixes = ['test'];
+
+foreach ($xpath['namespaces'] as $k => &$v);
+unset($v);
+foreach ($xpath as $k => &$v);
+unset($v);
+foreach ($prefixes as $k => &$v);
+unset($v);
+
+echo $doc->C14N(true, false, $xpath, $prefixes);
+?>
+--EXPECT--
+<contain xmlns="http://www.example.com/ns/foo"><bar></bar><bar></bar></contain>