High severity7.2NVD Advisory· Published Mar 10, 2026· Updated Jun 17, 2026
CVE-2026-31834
CVE-2026-31834
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
Umbraco.CmsNuGet | >= 15.3.1, < 16.5.1 | 16.5.1 |
Umbraco.CmsNuGet | >= 17.0.0, < 17.2.2 | 17.2.2 |
Affected products
3cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*range: >=15.3.1,<16.5.1
- (no CPE)range: >= 15.3.1, < 16.5.1
Patches
Vulnerability mechanics
References
3- github.com/advisories/GHSA-rhcg-3h8r-v6vpghsaADVISORY
- github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-rhcg-3h8r-v6vpnvdVendor AdvisoryWEB
- nvd.nist.gov/vuln/detail/CVE-2026-31834ghsaADVISORY
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