CVE-2026-31834 Details
Description
Umbraco is an ASP.NET CMS. From 15.3.1 to before 16.5.1 and 17.2.2, A privilege escalation vulnerability has been identified in Umbraco CMS. Under certain conditions, authenticated backoffice users with permission to manage users, may be able to elevate their privileges due to insufficient authorization enforcement when modifying user group memberships. The affected functionality does not properly validate whether a user has sufficient privileges to assign highly privileged roles. This vulnerability is fixed in 16.5.1 and 17.2.2.
A privilege escalation vulnerability exists in Umbraco CMS versions 15.3.1 prior to 16.5.1 and 17.2.2. This vulnerability allows authenticated backoffice users with user management permissions to elevate their privileges. The issue arises from inadequate authorization checks when users modify group memberships, enabling the assignment of highly privileged roles without proper validation. As a result, affected users may gain administrative rights, granting them full control over the CMS, including access to content, user management, and configuration settings.
Users can upgrade to Umbraco CMS versions 16.5.1 or 17.2.2 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Mar 11, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-rhcg-3h8r-v6vp | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-269 | Improper Privilege Management | [email protected] |
| CWE-284 | Improper Access Control | [email protected] |
| CWE-862 | Missing Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| umbraco umbraco cms | >= 15.3.1, < 16.5.1 >= 17.0.0, < 17.2.2 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Mar 18, 2026 | Initial Analysis | [email protected] |
| Mar 10, 2026 | New CVE Received | [email protected] |