CVE-2026-31834

high

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.

References

https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-rhcg-3h8r-v6vp

Details

Source: Mitre, NVD

Published: 2026-03-10

Updated: 2026-03-18

Risk Information

CVSS v2

Base Score: 8.3

Vector: CVSS2#AV:N/AC:L/Au:M/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 7.2

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H