Read the docs
TI-2026-24387 Aliases CVE-2026-31834GHSA-rhcg-3h8r-v6vp

Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks

Priority LOW 34CWE-269Published · Updated

Key facts

Attack vector
Network
Privileges required
High
User interaction
None
Attack complexity
Low
Impact type
Privilege escalation, Security bypass
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-269 and CWE-284.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00376 31st percentileScored 2026-11-07
Fix Fixed Umbraco-CMS (umbraco): 16.5.1, 17.2.1Umbraco.Cms (NuGet): 16.5.1, 17.2.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
umbracoUmbraco-CMS15.3.1 to before 16.5.1; 17.0.0 to before 17.2.116.5.1, 17.2.1Patch availableCNA
—Umbraco.Cms (NuGet)15.3.1 to before 16.5.116.5.1Patch availableGHSA-rhcg-3h8r-v6vp
—Umbraco.Cms (NuGet)17.0.0 to before 17.2.217.2.2Patch availableGHSA-rhcg-3h8r-v6vp
  • Umbraco-CMS Vendorumbraco Affected 15.3.1 to before 16.5.1; 17.0.0 to before 17.2.1 Fixed in 16.5.1, 17.2.1 Patch available CNA
  • Umbraco.Cms (NuGet) Vendor— Affected 15.3.1 to before 16.5.1 Fixed in 16.5.1 Patch available GHSA-rhcg-3h8r-v6vp
  • Umbraco.Cms (NuGet) Vendor— Affected 17.0.0 to before 17.2.2 Fixed in 17.2.2 Patch available GHSA-rhcg-3h8r-v6vp

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*15.3.1 to before 16.5.1; 17.0.0 to before 17.2.2Vulnerableumbraco
  • cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:* Versions 15.3.1 to before 16.5.1; 17.0.0 to before 17.2.2 Vulnerable ·umbraco

Remediation

  • Fix · CNA Umbraco-CMS (umbraco) Fixed in 16.5.1, 17.2.1
  • Fix · GHSA-rhcg-3h8r-v6vp Umbraco.Cms (NuGet) Fixed in 16.5.1 Advisory →
  • Fix · GHSA-rhcg-3h8r-v6vp Umbraco.Cms (NuGet) Fixed in 17.2.2 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-31834
  2. 2026-10-03 Alias added: GHSA-rhcg-3h8r-v6vp

References

Advisory 2

Other 1

  • TI-2025-41183 An arbitrary file upload vulnerability in Umbraco CMS v16.3.3 allows attackers to execute… CVSS 3.1CRITICAL 10.0
  • TI-2012-05477 Umbraco CMS < 4.7.1 codeEditorSave.asmx RCE CVSS 4.0CRITICAL 9.3
  • TI-2021-22392 Umbraco v8.14.1 - 'baseUrl' SSRF CVSS 4.0MEDIUM 6.9
  • TI-2024-36846 A stored cross-site scripting (XSS) vulnerability in Umbraco CMS v14.3.1 allows attackers… CVSS 3.1MEDIUM 6.5
  • TI-2019-15240 Umbraco CMS 4.11.8 through 7.15.10, and 7.12.4, allows Remote Code Execution by… CVSS 3.1HIGH 7.2
  • TI-2020-04738 Cross-site scripting in Umbraco CMS CVSS 3.1MEDIUM 5.4
See all 56 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences