diff --git a/ext/phar/phar_object.c b/ext/phar/phar_object.c
index 407edda0fbf..75aadfbc540 100644
--- a/ext/phar/phar_object.c
+++ b/ext/phar/phar_object.c
@@ -1477,7 +1477,7 @@ static int phar_build(zend_object_iterator *iter, void *puser TSRMLS_DC) /* {{{
 			}
 
 			close_fp = 0;
-			opened = (char *) estrndup(str, sizeof("[stream]") + 1);
+			opened = (char *) estrndup(str, sizeof("[stream]") - 1);
 			goto after_open_fp;
 		case IS_OBJECT:
 			if (instanceof_function(Z_OBJCE_PP(value), spl_ce_SplFileInfo TSRMLS_CC)) {