CVE-2026-114643: Duplicate geometry fields via unvalidated GeoJSON extra members

The MongoDB C# Driver writes GeoJSON extra members without checking whether their names collide with reserved GeoJSON members such as type and coordinates. An application that places user-supplied field names into these extra members can store documents with duplicate geometry fields, so the server and the driver resolve different values for the same record. Affected records can also become unreadable through the driver, interrupting application code that reads them.