Bulk write with options may read invalid memory

The MongoDB C driver can crash or read sensitive data when someone passes very large option values to bulk write operations. This happens because the code doesn't properly validate the size of these options before processing them.

A buffer overflow vulnerability exists in mongoc_bulk_operation_t when processing oversized options parameters. The vulnerability allows an attacker with the ability to control bulk operation options to trigger out-of-bounds memory reads, potentially leading to information disclosure or denial of service. Affected code lacks proper bounds checking during option parsing.