CVE-2026-31833

MEDIUM

6.7

Description

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.

CVE Details

CVSS v3.1 Score6.7

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredHIGH

User InteractionNONE

Published3/10/2026

Last Modified3/18/2026

Sourcenvd

Honeypot Sightings0

Affected Products

umbraco:umbraco_cms

Weaknesses (CWE)

CWE-79

References

https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-vrqc-59mw-qqg7(security-advisories@github.com)

IOC Correlations

No correlations recorded

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