diff --git a/ext/standard/array.c b/ext/standard/array.c
index 4896ac44a727d..37c80e0989caa 100644
--- a/ext/standard/array.c
+++ b/ext/standard/array.c
@@ -5762,6 +5762,7 @@ PHP_FUNCTION(array_diff)
 
 		for (i = 1; i < argc; i++) {
 			if (Z_TYPE(args[i]) != IS_ARRAY) {
+				zend_tmp_string_release(tmp_search_str);
 				zend_argument_type_error(i + 1, "must be of type array, %s given", zend_zval_value_name(&args[i]));
 				RETURN_THROWS();
 			}
diff --git a/ext/standard/tests/array/array_diff_leak_custom_type_checks.phpt b/ext/standard/tests/array/array_diff_leak_custom_type_checks.phpt
new file mode 100644
index 0000000000000..77aef0ccc08b2
--- /dev/null
+++ b/ext/standard/tests/array/array_diff_leak_custom_type_checks.phpt
@@ -0,0 +1,14 @@
+--TEST--
+array_diff() memory leak with custom type checks
+--FILE--
+<?php
+
+try {
+    array_diff([123], 'x');
+} catch (TypeError $e) {
+    echo $e->getMessage(), "\n";
+}
+
+?>
+--EXPECT--
+array_diff(): Argument #2 must be of type array, string given