High

Umbraco allows possible Admin-level access to backoffice without Auth under rare conditions

  • Disclosed: 13.07.2023
  • Updated: 11.10.2026 11:22

Under rare conditions, a restart of Umbraco can allow unauthorized users to gain admin-level permissions.

Impact

An unauthorized user gaining admin-level access and permissions to the backoffice.

Patches

10.6.1, 11.4.2, 12.0.1

Workarounds

  • Enabling the Unattended Install feature will mean the vulnerability is not exploitable.
  • Enabling IP restrictions to */install/* and */umbraco/* will limit the exposure to allowed IP addresses.

Affected software

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PlatformPackageVulnerable versionsFixed in
.NET (NuGet) Umbraco.Cms.Infrastructure >= 9.0.0, < 10.6.1, >= 11.0.0, < 11.4.2, >= 12.0.0, < 12.0.1 10.6.1, 11.4.2, 12.0.1
.NET (NuGet) Umbraco.Cms.Web.BackOffice >= 9.0.0, < 10.6.1, >= 11.0.0, < 11.4.2, >= 12.0.0, < 12.0.1 10.6.1, 11.4.2, 12.0.1

References

CVSS score 7.5/10
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-284
Platform
.NET (NuGet)
Package
Umbraco.Cms.Infrastructure, Umbraco.Cms.Web.BackOffice
Disclosed
13.07.2023
Updated
11.10.2026 11:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-h8wc-r4jh-mg7m - CC BY 4.0

Vulnerability history: Umbraco.Cms.Infrastructure

All published vulnerabilities of this package (.NET (NuGet)), newest first. Shows whether this is a one-off slip or a package that needs watching.

This is the only known vulnerability of this package.

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