CVE-2026-31833
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.
Published:Mar 10, 2026
Last Modified:Apr 16, 2026
EPS:Mar 10, 2026
EPSS Score:0.00063
CVSS Score:6.7
Affected Products
Vendor
Product
Action
Vendor
Umbraco
Product
Cms
Umbraco
Cms
Vendor
Umbraco
Product
Umbraco Cms
Umbraco
Umbraco Cms
Exploits
No exploit reference
Common Weakness Enumeration
Common Attack Pattern Enumeration and Classification (CAPEC)
Related CVEs
Common Vulnerability Scoring System
Attack Vector
Network
Adjacent
Local
Physical
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
