AIKIDO-2026-339928
Umbraco.Cms is vulnerable to Incorrect Authorization
88
High Risk
This Affects:
Umbraco.CmsTL;DR
Umbraco.Cms Management API template create, update, and delete endpoints allow Content-only backoffice users to mutate Templates. Those operations should require Settings-section access. Under the default BackofficeDevelopment runtime mode, template content is compiled as Razor and executed on the server, which can lead to remote code execution. The fix requires Settings-section authorization on template mutations and related Settings-only Management API operations.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range.
Background info
Umbraco.Cms is vulnerable to Incorrect Authorization in versions 15.2.0 - 17.6.1 and 18.0.0 - 18.1.0.
How to fix this
Upgrade the Umbraco.Cms library to the patch version.
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