Services - Critical - Arbitrary Code Execution - SA-CONTRIB-2017-003
This module provides a standardized solution for building API's so that external clients can communicate with Backdrop.
The module accepts user submitted data in PHP's serialization format ("Content-Type: application/vnd.php.serialized") which can lead to arbitrary remote code execution.
This vulnerability is mitigated by the fact that an attacker must know your Service Endpoint's path, and your Service Endpoint must have "application/vnd.php.serialized" enabled as a request parser.