CVE-2025-48953: Umbraco CMS

Medium severity, CVSS 6.5. EPSS: 0.2% chance of exploitation in the next 30 days.

Umbraco is an ASP.NET content management system (CMS). Starting in version 14.0.0 and prior to versions 15.4.2 and 16.0.0, it's possible to upload a file that doesn't adhere with the configured allowable file extensions via a manipulated API request. The issue is patched in versions 15.4.2 and 16.0.0. No known workarounds are available.

Affected products

• Umbraco Umbraco CMS: from 14.0.0, before 15.4.2 (fixed in 15.4.2)

Published 2025-06-03. Last modified 2026-06-17.