CVE-2026-31832: Umbraco Backoffice API Allows Unauthorized Modification of Domain Data
Description A broken object-level authorization vulnerability exists in a backoffice API endpoint that allows authenticated users to assign domain-related data to content nodes without proper authorization checks.
The issue is caused by insufficient authorization enforcement on the affected API endpoint, whereby via an API call, domains can be set on content nodes that the editor does not have permission to access (either via user group privileges or start nodes).
Impact An attacker can modify domain configurations for content nodes they are not permitted to edit. This may result in malicious or unintended routing behaviour, service disruption, and potential disclosure of configuration-related information.
Patches The issue is patched in 16.5.1 and 17.2.2.
Workarounds There is no workaround other than upgrading.
Other sources
Umbraco is an ASP.NET CMS. From 14.0.0 to before 16.5.1 and 17.2.2, A broken object-level authorization vulnerability exists in a backoffice API endpoint that allows authenticated users to assign domain-related data to content nodes without proper authorization checks. The issue is caused by insufficient authorization enforcement on the affected API endpoint, whereby via an API call, domains can be set on content nodes that the editor does not have permission to access (either via user group privileges or start nodes). This vulnerability is fixed in 16.5.1 and 17.2.2.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-31832?
CVE-2026-31832 has been classified as a high severity vulnerability due to its potential for unauthorized modification of domain data.
How do I fix CVE-2026-31832?
To fix CVE-2026-31832, upgrade Umbraco to the latest version, specifically version 16.5.1 or 17.2.2 and later.
What versions of Umbraco are affected by CVE-2026-31832?
CVE-2026-31832 affects Umbraco versions from 14.0.0 to before 16.5.1 and from 17.2.2 and earlier.
What type of vulnerability is CVE-2026-31832?
CVE-2026-31832 is a broken object-level authorization vulnerability that allows unauthorized access to domain-related data in the backoffice API.
Can authenticated users exploit CVE-2026-31832?
Yes, authenticated users can exploit CVE-2026-31832 to modify domain data due to insufficient authorization checks in the API.