CVE-2026-31833

6.7 mediumEPSS 0.3%

Medium (6.7) in umbraco umbraco cms. EPSS 0.3% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

6.7 medium

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

EPSS: 0.3% chance of exploitation in the next 30 days; higher than 20% of CVEs (scores of 2026-10-31)
CWE: CWE-79
Published: 2026-03-10
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

umbraco:umbraco_cms

References

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

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