GHSA-JJXQ-FF2G-95VH Twig has unguarded calls to `__isset()` and to array-accesses when the sandbox is enabled

Description In a sandbox, and attacker can access attributes of Array-like objects as they were not checked by the security policy. They are now checked via the property policy and the isset method is now called after the security check. This is a BC break. Resolution The sandbox mode now ensures...