Threat model triage

Threat Model — Triage (route one finding)

The consumer side of the model. Given an inbound finding and a finished (or drafted) threat model, assign exactly one disposition from the closed §1.17 set, citing the section that licenses it. The response is "see threat model §X", not ad-hoc prose.

Requires a threat model produced by the threat-model orchestrator (or an equivalent document following output-structure.md). If no such model exists, stop and recommend producing one first.

Route from the prose and the threat-model.yaml sidecar, never from the threat-model.json export. The JSON drops disposition_precedence, disclaimed-property tiers, and known-non-finding component/symptom scope, so a consumer holding only the JSON cannot apply §1.17 first-match ordering or the security-critical floor. It states the contract; it cannot route a report against it.

Routing algorithm (the §1.1 triager quick-start)

1. Locate the sink → look up its row in the §1.7 input-trust table (or the §1.8 output statement, for findings about what downstream consumers may assume).
2. Locate the contract dimension → for state corruption, overflow, recursion, callback execution, deserialization, lifecycle, concurrency, or complexity findings, consult the component's contract-dimension row and its routed owning claim in §1.3/§1.5/§1.7/§1.10/§1.11/§1.12 or unresolved question in §1.18. Do not infer failure semantics from the parameter trust row alone.
3. Check the attacker capability and control kind the finding requires against §1.7/§1.10. Distinguish control of data from control of size, type/class, callback code, object topology, collaborator implementation, or serialized state.
4. Check the affected component against §1.2/§1.3, and any required build flag against §1.6.
5. If the root cause lies in a dependency, apply §1.9.
6. Check §1.15 for an exact known non-finding match: same component or sink, symptom/attack class, and required conditions, with a current stable discharge reference. Textual resemblance is insufficient.
7. Apply §1.17's first-match precedence and assign exactly one disposition, citing the licensing section and provenance. If none fits, assign MODEL-GAP and trigger §1.16 — do not improvise.

The closed disposition set (§1.17)

Disposition	When	Licensed by
VALID	Violates a claimed property via an in-scope adversary and input.	§1.11, §1.7, §1.10
VALID-HARDENING	No §1.11 property violated, but a §1.14 misuse is easy enough to harden. Private; maintainer discretion; usually no CVE.	§1.14
OUT-OF-MODEL: trusted-input	Needs attacker control of a parameter marked trusted.	§1.7
OUT-OF-MODEL: adversary-not-in-scope	Needs an excluded attacker capability.	§1.10
OUT-OF-MODEL: unsupported-component	Lands in out-of-scope code.	§1.3
OUT-OF-MODEL: non-default-build	Requires a configuration explicitly marked dev-only, discouraged for the modeled use, or unsupported; non-default alone is insufficient.	§1.6
OUT-OF-MODEL: dependency-contract	Root cause is a dependency failing its own contract; usage conformant. Forward upstream, don't just close.	§1.9
BY-DESIGN: property-disclaimed	Concerns a property explicitly not provided.	§1.12
KNOWN-NON-FINDING	Matches a documented recurring false positive.	§1.15
MODEL-GAP	Fits none of the above → revise the model.	triggers §1.16

Guardrails

• Exactly one disposition. Apply §1.17's precedence when multiple preconditions fail. Report MODEL-GAP only when the model is silent or genuinely contradictory, not merely because two predicates are true.
• MODEL-GAP is not "other". It means the model is incomplete: the correct response is to add the property to §1.11/§1.12 (via threat-model-authoring), not to make an ad-hoc call on the report.
• Closure constraint (all statuses), governed by the declared triage policy. Any disposition that closes a report against the reporter (OUT-OF-MODEL: *, BY-DESIGN: *, KNOWN-NON-FINDING) must be licensed by a documented or maintainer claim, with one policy-scoped exception for assumption:
  • An inferred licensing claim always escalates instead of closing.
  • Read the header's triage policy. Under strict (default) an assumption also escalates only. Under relaxed an assumption may close the low-blast-radius routes — trusted-input, adversary-not-in-scope, unsupported-component, non-default-build, and a non-security-critical property-disclaimed — as a provisional close: cite the QN, note it re-opens on challenge, and leave the §1.18 item open.
  • Security-critical floor (both policies). An assumption never licenses KNOWN-NON-FINDING, a property-disclaimed whose property is security-critical, or dependency-contract; those escalate unless documented / maintainer.
  • Silence floor (both policies, every provenance). A §1.12 disclaimer that rests on the absence of a statement rather than on a stated limit never closes a security-critical report, a KNOWN-NON-FINDING, or dependency-contract — even tagged documented. Escalate instead.
  • An untiered §1.12 disclaimer is treated as security-critical, not as the weaker case. Do not read a blank tier as permission.
  • VALID routings are unaffected. A model marked accepted while retaining inferred or assumption claims is invalid; return it for status/model correction.
• An escalated finding is not a MODEL-GAP. Escalation means the route is right and the authority to use it is missing; MODEL-GAP means there is no route. Keep the disposition, mark it escalated, and name the §1.18 question that would unblock it. Do not feed it into the §1.16 revision loop — that loop is for genuine gaps, and filling it with escalations manufactures phantom model defects.
• Cite provenance. When a disposition closes a report, cite the tagged claim (e.g., "not a bug — §1.12 disclaims this property (maintainer, 2025-03)", or "provisionally out of model — §1.7 (assumption, Q6) under relaxed policy; re-open on challenge").

Output

The disposition and its status, written as DISPOSITION (status) — for example OUT-OF-MODEL: trusted-input (escalated). The status is one of:

Status	Meaning
closed	Licensed by a documented or maintainer claim. The report is answered.
provisional	A relaxed-policy assumption close. Cite the QN; re-opens on challenge.
escalated	The route is right but its license cannot close it. Name the blocking QN.

VALID and MODEL-GAP are not closes and take no status qualifier.

Also report the citing section(s), the provenance of the licensing claim, and — for MODEL-GAP or a two-way route — the model-revision or sharpening recommendation to hand back to the orchestrator.