CVE-2026-31833

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.

Affected Software

VendorProductVersion RangeStatus
umbracoUmbraco-CMS>= 16.2.0, < 16.5.1affected
umbracoUmbraco-CMS>= 17.0.0, < 17.2.1affected

Weaknesses

  • CWE-79: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: total

References