A wildcard relation is a schema construct that lets one relation apply to every subject of a declared type. In authorization systems, it is used to express public access or broad eligibility without writing a separate relationship for each user, while still keeping the model type-aware and manageable.
How wildcard relations work
A wildcard relation is a modeling shortcut, not a permission shortcut. It lets the authorization schema say that one relationship applies to all subjects of a declared type, so policy authors can express broad eligibility or public access without duplicating relationships for each individual principal.
That design keeps the graph manageable while preserving type awareness. The relation still names a concrete subject type, which means the model remains structured enough for evaluation, review, and future extension rather than collapsing into an unbounded allow rule.
In practice, wildcard relations are most useful when the same rule would otherwise need to be repeated many times, such as every authenticated user, every member of a tenant, or every object of a known class. They are often easier to read than a long list of equivalent edges, but they also demand careful naming so the broad scope is obvious to reviewers.
Where wildcard relations fit in authorization design
Wildcard relations usually sit inside a relationship-based authorization model, where access decisions are derived from typed relationships instead of only from static role assignment. That makes them especially valuable in systems that need flexible inheritance, broad defaults, or policy graphs that can be queried consistently across many object types.
They also help separate policy intent from storage mechanics. Instead of inserting a relationship for every principal-object pair, the schema can declare that a relation covers the full subject class, then let the enforcement layer resolve membership and context at decision time.
The trade-off is that the schema becomes more expressive, but also easier to misunderstand if teams treat the wildcard as a convenience layer rather than a real authorization primitive. A wildcard relation should therefore be read as part of the access model itself, not as a comment or implementation detail.
Why wildcard relations are powerful in large systems
Wildcard relations are useful because they reduce policy sprawl and make common access patterns explicit. In large environments, that can improve maintainability, reduce duplication, and make it easier to reason about the intended scope of a permission model.
They are also a natural fit for default visibility rules, tenant-wide sharing, or other cases where the same relationship applies to a broad population. When the model is type-aware, wildcarding can preserve the difference between “everyone of this type” and “anyone at all,” which matters for review and later policy evolution.
The benefit is strongest when the term maps cleanly to a stable subject class. If the subject type is too broad, the wildcard can become an abstraction that hides important distinctions and makes access review harder instead of easier.
Risk and Threat Considerations
Wildcard relations can create unintended exposure when the declared subject type is broader than the policy author realizes, or when the model is later reused in a new context. A relation meant to simplify public or group-wide access can become a high-impact overreach point if reviewers assume the wildcard is narrower than it really is.
Failure mechanism: Mis-scoped type declarations, permissive defaults, or ambiguous naming can cause a wildcard relation to grant access to more principals than intended, especially after schema changes or inheritance updates.
Impact: The result is often authorization bypass, overbroad data exposure, or a policy graph that appears precise but actually applies far more widely than expected.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST CSF 2.0 and CIS Controls v8 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST CSF 2.0 | PR.AC-4 — Access Permissions and Authorizations Management | Wildcard relations define broad authorization scope across subject types. |
| Recommendation — Limit wildcard relations to tightly defined subject types and review their effective access scope. | ||
| CIS Controls v8 | 5.3 — Manage Account Permissions and Group Membership | Wildcard relations can expand effective permissions across many principals. |
| Recommendation — Review broad relations as permission assignments and remove unintended access paths. | ||
Practitioner Guidance
What to watch for: Treat wildcard relations as governance-sensitive schema objects, not just syntax sugar. The main practitioner judgment is whether the declared subject type is genuinely the smallest safe scope for the intended access pattern, because that choice determines how safely the rule can evolve over time.
Common misunderstanding: Teams sometimes assume a wildcard is harmless because it still feels type-aware. In reality, the type boundary is the control boundary, so broad or loosely defined types can make a seemingly tidy model harder to audit than a few explicit relationships.
