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.

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History

Tue, 10 Mar 2026 22:00:00 +0000

Type Values Removed Values Added
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.
Title Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks
Weaknesses CWE-269
CWE-284
CWE-862
References
Metrics cvssV3_1

{'score': 7.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-10T21:53:49.153Z

Reserved: 2026-03-09T17:41:56.077Z

Link: CVE-2026-31834

cve-icon Vulnrichment

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cve-icon NVD

Status : Received

Published: 2026-03-10T22:16:21.567

Modified: 2026-03-10T22:16:21.567

Link: CVE-2026-31834

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses