CVE
CVE-2026-31834
Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks
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.
Package Versions Affected
Package Version
patch Availability
No items found.
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Fix Without Upgrading
Detect compatible fix
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Fix with a single pull request
CVSS Version
Severity
Base Score
CVSS Version
Score Vector
C
H
U
7.2
-
3.1
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
C
H
U
7.2
-
3.1
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Related Resources
No items found.
References
https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31834.json, https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-rhcg-3h8r-v6vp, https://nvd.nist.gov/vuln/detail/CVE-2026-31834
Basic Information
Ecosystem
