ISO 14971 risk estimation and evaluation process, risk acceptability criteria, and risk management file linking risks to controls.
CVSS-based security risk estimation distinct from safety probability/severity scales, acceptability threshold documented in the security risk management plan, with findings fed back to the ISO 14971 file.
Security risk assessment with CVSS scores and documented acceptability thresholds — applying safety probability scales to cybersecurity is a critical FDA and Notified Body finding.
Maps to
IEC 81001-5-1: §7.3 Estimation and evaluation of SECURITY risk
ISO 14971: §5.4 Identification of hazards and hazardous situations
IEC 62443-4-1: §SR-2
Requirement text
Estimate security risk using CVSS or a similar scoring method (e.g., MITRE, ISO/IEC Guide 51, ISO 14971). Evaluate estimated risks to determine whether they are acceptable. Inform the product risk management process about updates to the threat model.
Why this clause exists
Security risk estimation requires a framework different from ISO 14971 safety risk estimation because the key parameter in security risk — exploitability — is adversarially controlled rather than probabilistic. Safety risk estimation treats probability of harm occurrence as a property of the device and environment; security risk estimation must treat exploitability as a property of adversarial capability and access opportunity. FDA has explicitly rejected the use of ISO 14971-style probability scales for cybersecurity risk, noting that threat actors can increase their effort when attack payoffs are high. CVSS was developed specifically to provide a standardized, reproducible scoring methodology that captures exploitability factors (attack vector, attack complexity, privileges required, user interaction) independently from impact factors (confidentiality, integrity, availability impact), allowing organizations to estimate security risk in a way that regulators and operators can independently verify and compare. IEC 81001-5-1:2021 clause 7.3 requires security risk estimation and evaluation using such a methodology, and CVSS v3.1 represents the current industry standard for satisfying this requirement in the medical device context.
What changed
IEC 81001-5-1:2021 is the first standalone cybersecurity standard purpose-built for health software and medical device software. Published in December 2021, it was adapted from IEC 62443-4-1 (industrial control systems security) to address the unique safety and regulatory context of medical devices — adding health-specific requirements that account for patient safety, clinical workflows, and the manufacturer-HDO relationship.
The standard mirrors IEC 62304's lifecycle structure but adds security-specific activities at every phase — planning, development, testing, release, and maintenance. It requires security risk management to be integrated with ISO 14971 safety risk management, not treated as a separate IT concern. FDA formally recognized it as Consensus Standard 13-122 on December 19, 2022 and references it as providing one acceptable framework for satisfying the cybersecurity requirements of Section 524B(b)(2), which requires manufacturers to design, develop, and maintain processes and procedures to provide a reasonable assurance that cyber devices and related systems are cybersecure.
EU MDR harmonization was originally targeted for May 2024 but postponed to May 2028. Despite this delay, Notified Bodies and Competent Authorities universally recognize it as "state of the art" for health software cybersecurity under MDR GSPR Annex I, Section 17.2. Missing or inadequate cybersecurity documentation is already a top cause of Notified Body major non-conformities for SaMD. A December 2025 Interpretation Sheet (ISH1:2025) clarified software item classification into maintained, supported, and required software categories, affecting risk transfer and post-market obligations.
Common gaps (what we see in audits)
- Risk estimation uses safety-derived scales inappropriate for cybersecurity — Cybersecurity risks are estimated using probability/severity scales designed for safety risks under ISO 14971. FDA rejects 'probability of occurrence' for cybersecurity because security exploits are not random events. Risk must be assessed based on exploitability, attacker capability, and attack complexity using frameworks like CVSS or SSVC.