CVE-2023-49278: Umbraco CMS

Medium severity, CVSS 5.3. EPSS: 0.5% chance of exploitation in the next 30 days.

Umbraco is an ASP.NET content management system (CMS). Starting in version 8.0.0 and prior to versions 8.18.10, 10.8.1, and 12.3.4, a brute force exploit can be used to collect valid usernames. Versions 8.18.10, 10.8.1, and 12.3.4 contain a patch for this issue.

Affected products

• Umbraco Umbraco CMS: from 8.0.0, before 8.18.10 (fixed in 8.18.10); from 10.0.0, before 10.8.1 (fixed in 10.8.1); from 12.0.0, before 12.3.4 (fixed in 12.3.4)

Published 2023-12-12. Last modified 2026-06-17.