Fix bug #24399 from an excellent test case by edin

diff --git a/Zend/zend_builtin_functions.c b/Zend/zend_builtin_functions.c
index 0447917e7e03a84de23097e11d2d5d4cffcd0046..ba532610772d9e517b0cf03d82e0b3805ea0b4b5 100644 (file)
--- a/Zend/zend_builtin_functions.c
+++ b/Zend/zend_builtin_functions.c
@@ -616,6 +616,9 @@ static void is_a_impl(INTERNAL_FUNCTION_PARAMETERS, zend_bool only_subclass)
        } else {
                if (only_subclass) {
                        instance_ce = Z_OBJCE_PP(obj)->parent;
+                       if (!instance_ce) {
+                               RETURN_FALSE;
+                       }
                } else {
                        instance_ce = Z_OBJCE_PP(obj);
                }