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Umbraco Backoffice API Allows Unauthorized Modification of Domain Data

Moderate severity GitHub Reviewed Published Mar 10, 2026 in umbraco/Umbraco-CMS • Updated Mar 11, 2026

Package

nuget Umbraco.Cms (NuGet)

Affected versions

>= 14.0.0, < 16.5.1
>= 17.0.0, < 17.2.2

Patched versions

16.5.1
17.2.2

Description

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.

References

@AndyButland AndyButland published to umbraco/Umbraco-CMS Mar 10, 2026
Published by the National Vulnerability Database Mar 10, 2026
Published to the GitHub Advisory Database Mar 11, 2026
Reviewed Mar 11, 2026
Last updated Mar 11, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(12th percentile)

Weaknesses

Authorization Bypass Through User-Controlled Key

The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. Learn more on MITRE.

CVE ID

CVE-2026-31832

GHSA ID

GHSA-fpvf-fvp5-996r

Source code

Credits

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