A caller who was never granted access can still read content that the organization intended to keep private. In practice that can expose member-only pages, internal notices, unpublished campaign material, or gated documents. The outcome is unauthorized disclosure through an indirect path, even though the protected node itself may still reject direct access.
How referenced-node delivery creates an indirect disclosure path
When a delivery API resolves referenced nodes on behalf of a caller, access checks can become fragmented. The protected object may still enforce its own permissions, but the response can include linked or embedded content from a node that is more broadly reachable. That is why the real question is not only “can I fetch the parent object?” but “what else can be traversed from it?”
In practice, this pattern turns object relationships into an authorization boundary. If the API treats the reference as safe because the top-level object is public, a caller may retrieve content that was never meant to be exposed directly. OWASP API Security Top 10 is relevant here because broken object-level and function-level authorization often show up exactly as indirect reads through nested or referenced resources.
Delivery APIs are especially prone to this when they flatten content for convenience, prefetch related nodes, or reuse a single resolver across public and private paths. The security issue is not that references exist, it is that authorization is assumed to be complete once the first node is allowed. Any reference expansion that crosses a trust boundary needs its own authorization decision.
Why the exposure matters operationally
The impact is unauthorized disclosure, but the practical harm depends on what the referenced nodes contain. Publicly reachable reference chains can expose member-only pages, internal notices, unpublished campaigns, drafts, gated documents, or other content the organisation expected to remain hidden. In a content platform, that can create privacy issues, reputational damage, or premature publication of material that affects legal, communications, or commercial plans.
This is not limited to obvious “secret” data. A weakly protected reference chain can also reveal metadata, identifiers, or internal structure that helps an attacker map the application. If the delivery API returns enough detail to enumerate related nodes, it can become a discovery channel for broader access abuse. The exposed surface is often larger than the single page the caller asked for.
The same failure pattern also appears in API-centric breach scenarios. NHIMG’s T-Mobile API breach 2023 shows how API access paths can be abused to pull large volumes of data without valid authorisation when the access model is too permissive or the checks are too shallow.
What to verify before you trust referenced-node delivery
Authorisation must be checked at the level of every resolved node, not only the entry point. If a public object can reference private child objects, the API needs to confirm whether the caller may see each child in the current context, with the current scope, and through the current delivery path. That verification should cover direct reads, nested expansion, search results, previews, and any caching layer that can replay content.
- Verify that reference expansion cannot bypass object-level permissions.
- Verify that the response only includes nodes the caller is allowed to see in the current context.
- Verify that public delivery paths do not leak private node identifiers, titles, or snippets.
- Verify that caches, CDNs, and precomputed payloads preserve the same access rules as live requests.
For API-heavy systems, the design assumption should be that a reference is untrusted until authorised. That means the content resolver, not just the top-level endpoint, must enforce the policy. Where the application uses audience-restricted tokens or delegated access, the reference check should still be tied to the effective permissions of the caller, not the visibility of the parent object.
Risk and Threat Considerations
Referenced-node delivery creates a classic indirect object exposure problem: the attacker does not need to break the private object’s direct control if they can reach it through a public parent, preview, embed, or expansion path. The failure is especially dangerous when the system assumes that “public enough to traverse” is the same as “public enough to read.”
Failure mechanism: A public or low-privilege node contains a reference to a restricted node, and the delivery API resolves that reference without reapplying object-level authorization on the downstream object.
Impact: Attackers or unauthorised users can read content that should have stayed private, and they may also learn enough about the structure of the content graph to enumerate additional sensitive nodes.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP API Security Top 10 addresses the attack surface, NIST SP 800-53 Rev 5 sets the technical controls, and ISO/IEC 27001:2022 defines the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP API Security Top 10 | API1 — Broken Object Level Authorization | Referenced-node delivery can expose private objects through indirect reads. |
| API5 — Broken Function Level Authorization | Delivery APIs often fail when expansion or preview functions exceed caller rights. | |
| Recommendation — Enforce object-level checks on every resolved node, not just the parent object. Restrict expansion and preview functions to the caller's effective permissions. | ||
| NIST SP 800-53 Rev 5 | AC-3 — Access Enforcement | Each resolved node needs enforced access decisions before disclosure. |
| AC-6 — Least Privilege | Reference traversal should only reveal the minimum content the caller is entitled to see. | |
| Recommendation — Apply access enforcement at the object and subobject level for all delivered content. Limit reference expansion to the minimum data and context required. | ||
| ISO/IEC 27001:2022 | A.5.15 — Access control | This disclosure path is an access-control failure across linked content. |
| Recommendation — Define and enforce access rules for referenced content paths and expansions. | ||
Practitioner Guidance
What to prioritise: Treat reference resolution as an access-control decision, not a rendering detail. The first control to harden is the resolver path that expands linked nodes, because that is where indirect disclosure usually enters.
What to verify: Check whether the API enforces the same policy for direct fetches, expanded references, search previews, and cached representations. If those paths do not behave the same way, the implementation is not genuinely closed.
Common mistake: Teams often validate the top-level object and assume downstream references inherit that decision automatically. That assumption is unsafe whenever public and private content can coexist in the same graph.
Practitioner takeaway: If a caller can see a parent object, do not assume they can see everything it points to, each referenced node needs its own authorization outcome.
Related resources from NHI Mgmt Group
- How should security teams reduce exposure when a headless CMS delivery API bypasses page-level access controls on referenced content?
- Who is accountable when a public API leaks data through valid access?
- What happens when firewall configuration backups are exposed through compromised API access?
- Why does exposing Kubernetes access through standing credentials or a public API server increase security risk?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on September 30, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
