An opinionated playbook for operationalising AI risk under ISO 42001 — the AI-specific threat taxonomy your register is missing, a scoring approach that works when likelihood is unknowable, and how the standard fits with ISO 27001 and the EU AI Act.
Information-security risk registers were built around a threat model where the attacker is external, the asset is data, and the control is a technical safeguard. AI changes all three. The "attacker" is sometimes the model itself producing a confidently wrong answer. The "asset" includes training data, model weights, prompts and outputs. The "control" is increasingly a human-in-the-loop check or a guardrail policy, not a firewall rule.
Bolting AI onto the existing cyber risk taxonomy hides the new risks. A risk titled "AI hallucination" landed alongside "Phishing of finance team" loses both the specificity and the scoring discipline that 42001 demands. AI needs its own family in your taxonomy, with its own sub-categories and its own scoring sub-criteria.
The seven families we use with clients running ISO 42001 alongside ISO 27001:
| Family | Example risks | Primary treatment lens |
|---|---|---|
| Model behaviour | Hallucination, bias, unsafe content, refusal failure | Evaluation, guardrails, human review |
| Model lifecycle | Drift, performance decay, undocumented fine-tunes | Monitoring, retraining cadence, change control |
| Data | Training-data leakage, PII in prompts, copyright | Data governance, DLP, contractual |
| Adversarial | Prompt injection, jailbreaks, data poisoning | Input/output filtering, red-teaming |
| Governance | Shadow AI, unsanctioned use, decision accountability | Acceptable-use policy, sanctioned-tools list |
| Vendor & supply chain | Foundation-model dependency, sub-processor opacity, model deprecation | Multi-vendor design, contractual SLAs, exit plans |
| Regulatory & reputational | EU AI Act non-conformity, discriminatory outcomes, transparency failures | Conformity assessment, DPIA/FRIA, disclosure |
Adopt all seven families even if you only use AI in two places today. The taxonomy is what makes future risks land cleanly in the register instead of being misfiled under "IT".
The conventional 5×5 asks: how likely is this to happen in the next 12 months? For model hallucination that question is meaningless — it happens on every other request at some baseline rate. The trick is to replace likelihood with a rate-per-opportunity proxy that maps cleanly to the 1–5 scale.
The standards are designed to coexist. Annex A of ISO 42001 contains 38 controls that overlap meaningfully with ISO 27001 Annex A — and the rest sit in the gap that 27001 was never designed to cover. A pragmatic mapping:
| ISO 42001 area | Reuse from ISO 27001 | New 42001-specific work |
|---|---|---|
| Leadership & policy | Top-level policy framework, roles | AI policy, AI ethics statement, AI roles & RACI |
| Risk management | 5×5 method, register, treatment workflow | AI-specific taxonomy, rate-based likelihood, fundamental-rights impact |
| Operational controls | Access, change, supplier, incident | Data governance for AI, model lifecycle, human oversight, transparency |
| Performance evaluation | Internal audit, management review | Model evaluation reports, bias and fairness testing |
| Improvement | Nonconformity & CAPA | AI-incident reporting, post-deployment monitoring |
The EU AI Act categorises systems as unacceptable, high-risk, limited-risk or minimal-risk. For any high-risk system, the Act expects a documented risk-management process, data governance, technical documentation, record-keeping, transparency, human oversight, accuracy/robustness/cybersecurity controls, and post-market monitoring. ISO 42001 gives you the management-system scaffold for almost all of it.
The practical 2026 pattern we recommend:
ISO-STANDARD.app supports the AI-specific taxonomy, rate-based likelihood scoring, asset-linked AI systems and the cross-mapping to ISO 27001 — so your AIMS and ISMS share one register instead of fighting over it.
ISO-STANDARD.app ships a ready-to-adopt ISO 42001 AI management workspace with the risk register, controls catalogue, policies and audit-ready exports already wired together — no spreadsheet sprawl, no consultant lock-in.
Prefer a conversation? Email hello@iso-standard.app — a real human responds within one business day.
