A modular risk management framework for integrating cybersecurity and patient safety in medical device software...

Medical device software operates in increasingly connected environments where cybersecurity incidents can directly compromise patient safety. While established safety risk management standards such as ISO 14971 provide mature frameworks for managing unintended hazards, they implicitly assume non-malicious causes and that risks are amenable to probability estimation. Cybersecurity risk management, by contrast, addresses adversarial threats, exploitability, and inherent uncertainty, requiring fundamentally different vocabularies, risk models, and acceptance criteria. In practice, organisations often force these domains into a single monolithic risk structure, producing terminological confusion, incommensurable risk values, and siloed assessments with no mechanism to escalate findings between safety and security processes. This paper presents the Modular Risk Schema Framework, a concrete, repeatable approach to integrating safety and cybersecurity risk management in medical device software development. Rather than forcing divergent domains into a unified risk model, the framework supports multiple domain-specific risk schemas in parallel, each with its own information model, risk model, acceptance criteria, and level of rigor, connected through explicit traceability interfaces. These interfaces ensure systematic escalation of safety-relevant cybersecurity risks and identification of safety controls with security implications. The framework is embedded within a single quality management system, enforces security by design through phase-gated deliverables aligned with the software lifecycle, and is designed for implementation in modern application lifecycle management environments without dependence on specific tools. The approach has been developed and applied in industrial contexts and aligns with the requirements of ISO 14971, IEC 62304, IEC 81001-5-1, and current regulatory guidance.