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TI-2026-24386 Aliases CVE-2026-31833GHSA-vrqc-59mw-qqg7

Umbraco has Stored XSS in UFM Rendering Pipeline via Permissive DOMPurify Attribute Filtering

Priority LOW 31CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
High
User interaction
None
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
High · High · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

Umbraco is an ASP.NET CMS. From 16.2.0 to before 16.5.1 and 17.2.2, An authenticated backoffice user with access to Settings can inject malicious HTML into property type descriptions. Due to an overly permissive attributeNameCheck configuration (/.+/) in the UFM DOMPurify instance, event handler attributes such as onclick and onload, when used within Umbraco web components (umb-*, uui-*, ufm-*) were not filtered. 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 0.00302 23rd 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-CMS16.2.0 to before 16.5.1; 17.0.0 to before 17.2.116.5.1, 17.2.1Patch availableCNA
—Umbraco.Cms (NuGet)16.2.0 to before 16.5.116.5.1Patch availableGHSA-vrqc-59mw-qqg7
—Umbraco.Cms (NuGet)17.0.0 to before 17.2.217.2.2Patch availableGHSA-vrqc-59mw-qqg7
  • Umbraco-CMS Vendorumbraco Affected 16.2.0 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 16.2.0 to before 16.5.1 Fixed in 16.5.1 Patch available GHSA-vrqc-59mw-qqg7
  • Umbraco.Cms (NuGet) Vendor— Affected 17.0.0 to before 17.2.2 Fixed in 17.2.2 Patch available GHSA-vrqc-59mw-qqg7

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*16.2.0 to before 16.5.1; 17.0.0 to before 17.2.2Vulnerableumbraco
  • cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:* Versions 16.2.0 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-vrqc-59mw-qqg7 Umbraco.Cms (NuGet) Fixed in 16.5.1 Advisory →
  • Fix · GHSA-vrqc-59mw-qqg7 Umbraco.Cms (NuGet) Fixed in 17.2.2 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-31833
  2. 2026-10-03 Alias added: GHSA-vrqc-59mw-qqg7

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