CVE-2026-69197: Umbraco: Delivery API leaks protected (Public Access) content through Content Picker / Multi-Node Tree Picker expansion
The Content Delivery API enforces member / Public Access protection only at the controller layer, against the node that is directly requested. When a public (unprotected) node references a protected node through a Content Picker or Multi-Node Tree Picker (including those nested inside Block List, Block Grid, or Rich Text Editor blocks), the Delivery API expands and serializes the protected node with no access check applied.
Similarly, configuration based restrictions based on aliases of allowed or disallowed content types are by-passed for referenced content items that are retrieved via property expansion.
As a result, an anonymous / unauthorized caller can retrieve a protected node's: - Name, route, and id — always, even without expansion, and - Full property values — when the request uses ?expand on the picker property. A direct request for the same protected node correctly returns 401 Unauthorized, which makes the leak easy to miss: the protection appears to work, but is bypassed via reference expansion.
Impact Confidential, member-gated content (e.g. pricing, internal documents, gated articles) referenced by any publicly readable node is disclosed to unauthenticated clients. No write/integrity or availability impact.
Highest impact when the Delivery API is publicly readable (DeliveryApi:PublicAccess: true). Still exploitable, at reduced severity, when the Delivery API is gated by the org-wide API key (the key holder still bypasses per-node Public Access).
Patches 13.15.1, 17.5.3, 18.0.2
References https://docs.umbraco.com/umbraco-cms/develop-with-umbraco/headless-and-apis/content-delivery-api
Other sources
Umbraco is an ASP.NET CMS. Prior to 13.15.1, 17.5.3, and 18.0.2, the Content Delivery API applies member and Public Access checks to the directly requested node but not to referenced nodes serialized through Content Picker or Multi-Node Tree Picker properties, including pickers nested in Block List, Block Grid, or Rich Text Editor blocks. When DeliveryApi:PublicAccess is enabled, an anonymous caller can retrieve a protected node's name, route, and id through an unprotected referencing node and use ?expand to retrieve full property values. When the Delivery API is instead gated by the organization-wide API key, a key holder can still bypass per-node Public Access through the same expansion path. The same RequestContextOutputExpansionStrategyV2 and ElementOnlyOutputExpansionStrategy path also bypasses allowed or disallowed content-type alias restrictions for referenced content. Direct requests for the protected node still return 401, and no integrity or availability impact is established. This issue is fixed in versions 13.15.1, 17.5.3, and 18.0.2.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
nuget/Umbraco.Cmsto a version that resolves this vulnerability.Fixed in 18.0.2 - Upgrade
Upgrade
nuget/Umbraco.Cmsto a version that resolves this vulnerability.Fixed in 17.5.3 - Upgrade
Upgrade
nuget/Umbraco.Cmsto a version that resolves this vulnerability.Fixed in 13.15.1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 13.15.1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 17.5.3 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 18.0.2 - Configuration
If you cannot immediately upgrade to 13.15.1, 17.5.3, or 18.0.2, disable public access by setting DeliveryApi:PublicAccess to false to prevent anonymous/unauthorized callers from using Content Picker / Multi-Node Tree Picker ?expand to retrieve protected node data.
Umbraco Delivery API DeliveryApi:PublicAccess = false
Event History
Frequently Asked Questions
Which deployments are exposed to anonymous access?
Deployments with DeliveryApi:PublicAccess enabled are exposed when an unprotected node references protected content through a Content Picker or Multi-Node Tree Picker. This also includes such pickers nested in Block List, Block Grid, or Rich Text Editor blocks.
What does an attacker need to retrieve protected content?
An anonymous attacker needs access to an unprotected referencing node and can use expansion of its picker properties to obtain referenced protected content. Initially, the referenced node's name, route, and ID may be exposed; using ?expand can return its full property values.
Does restricting the Delivery API with an organization-wide API key prevent this issue?
No. A holder of the organization-wide API key can still bypass per-node Public Access controls through the affected expansion path.
Are content-type alias allowlists or denylists effective for referenced content?
No. The affected RequestContextOutputExpansionStrategyV2 and ElementOnlyOutputExpansionStrategy paths bypass allowed and disallowed content-type alias restrictions for referenced content.
How can I tell whether direct access controls are still working?
A direct Delivery API request for a protected node returns 401. The exposure occurs when that protected node is serialized as referenced content from an unprotected node.