http://svn.php.net/viewvc?view=revision&revision=288945

--- ext/standard/file.c	2007-12-31 02:20:12.000000000 -0500
+++ ext/standard/file.c.oden	2009-10-20 08:15:07.000000000 -0400
@@ -826,6 +826,10 @@ PHP_FUNCTION(tempnam)
 	convert_to_string_ex(arg1);
 	convert_to_string_ex(arg2);
 
+	if (PG(safe_mode) &&(!php_checkuid(Z_STRVAL_PP(arg1), NULL, CHECKUID_ALLOW_ONLY_DIR))) {
+		RETURN_FALSE;
+	}
+
 	if (php_check_open_basedir(Z_STRVAL_PP(arg1) TSRMLS_CC)) {
 		RETURN_FALSE;
 	}