Brother printer bug in 689 models exposes default admin passwords

**Executive Summary:** Rapid7 disclosed eight vulnerabilities in Brother printers (and affected models from Fujifilm, Konica Minolta, Ricoh, and Toshiba), highlighting CVE-2024-51978 — a critical flaw allowing attackers to deterministically generate default administrator passwords by reversing the device's serial-number-based password algorithm; the issue affects hundreds of devices and cannot be fully remediated in existing hardware via firmware, so users must change default passwords, apply available firmware updates, and restrict administrative access.