Vulnerability · Published Mar 10, 2026 · Assigned by GitHub_M

CVE-2026-31834Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks

High 7.2

In plain English

A high-severity privilege mismanagement in Umbraco-CMS from umbraco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.2High

Exploit odds (30 days)0.4%top 68.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
NuGet	umbraco.cms	16.5.1	GHSA-rhcg-3h8r-v6vp
NuGet	umbraco.cms	17.2.2	GHSA-rhcg-3h8r-v6vp

Affected products (as reported)

Vendor	Product	Versions
umbraco	Umbraco-CMS	>= 15.3.1, < 16.5.1>= 17.0.0, < 17.2.1

Weakness: CWE-269, CWE-284, CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

References

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