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.
CVSS Metrics
- Vector
- CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L
- Attack Vector
- network
- Complexity
- low
- Privileges
- high
- User Action
- none
- Scope
- unchanged
- Confidentiality
- high
- Integrity
- high
- Availability
- low
- Weaknesses
- CWE-79
Metadata
- Primary Vendor
- UMBRACO
- Published
- 3/10/2026
- Last Modified
- 3/18/2026
- Source
- NIST NVD
- Note: Verify all details with official vendor sources before applying patches.
Affected Products
umbraco : umbraco_cmsumbraco : umbraco_cms
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