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.
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Affected Vendors & Products
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History
Tue, 10 Mar 2026 22:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Umbraco has Stored XSS in UFM Rendering Pipeline via Permissive DOMPurify Attribute Filtering | |
| Weaknesses | CWE-79 | |
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cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-03-10T21:51:51.407Z
Reserved: 2026-03-09T17:41:56.077Z
Link: CVE-2026-31833
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Status : Received
Published: 2026-03-10T22:16:21.410
Modified: 2026-03-10T22:16:21.410
Link: CVE-2026-31833
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OpenCVE Enrichment
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