CVE-2026-31834
published 2026-03-10CVE-2026-31834: 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…
PriorityP348high7.2CVSS 3.1
AVNACLPRHUINSUCHIHAH
EPSS
0.26%
16.9th percentile
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.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| umbraco | umbraco-cms | — | — |
| umbraco | umbraco-cms | — | — |
| umbraco | umbraco_cms | >= 15.3.1 < 16.5.1 | 16.5.1 |
| umbraco | umbraco_cms | >= 17.0.0 < 17.2.2 | 17.2.2 |
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OSV
Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks
osv·2026-03-11
CVE-2026-31834 [HIGH] Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks
Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks
### Description
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.
### Impact
An authenticated backoffice user may be able to escalate their privileges to Administrator level.
Successful exploitation results in full administrative control of the affected Umbraco CMS instance, including unrestricted access to content, user management, and config
GHSA
Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks
ghsa·2026-03-11
CVE-2026-31834 [HIGH] CWE-269 Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks
Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks
### Description
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.
### Impact
An authenticated backoffice user may be able to escalate their privileges to Administrator level.
Successful exploitation results in full administrative control of the affected Umbraco CMS instance, including unrestricted access to content, user management, and config
No detection rules found.
No public exploits indexed.
2026-03-10
Published