Medium

Umbraco Delivery API allows for cached requests to be returned with an invalid API key

  • Disclosed: 29.07.2025
  • Updated: 11.10.2026 11:23

Impact

Umbraco's content delivery API can be restricted from public access such that an API key must be provided in a header to authorize the request.

It's also possible to configure output caching, such that the delivery API outputs will be cached for a period of time, improving performance.

There's an issue when these two things are used together though in that the caching doesn't vary by the header that contains the API key. As such it's possible for a user without a valid API key to retrieve a response for a given path and query if it has recently been requested and cached by request with a valid key.

Patches

Patches will be available in 13.9.3, 15.4.4 and 16.1.1.

Workarounds

Workaround is to remove or reduce the time period of the output caching or to provide other restrictions to access the delivery API such as by IP.

References

Content delivery API documentation: https://docs.umbraco.com/umbraco-cms/reference/content-delivery-api

Affected software

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PlatformPackageVulnerable versionsFixed in
.NET (NuGet) Umbraco.Cms.Api.Delivery >= 13.0.0, < 13.9.3, >= 15.0.0, < 15.4.4, >= 16.0.0, < 16.1.1 13.9.3, 15.4.4, 16.1.1

References

CVSS score 5.3/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness (CWE)
CWE-200
Platform
.NET (NuGet)
Package
Umbraco.Cms.Api.Delivery
Disclosed
29.07.2025
Updated
11.10.2026 11:23

Sources and licenses

OSV / GitHub Advisory Database - GHSA-75vq-qvhr-7ffr - CC BY 4.0

Vulnerability history: Umbraco.Cms.Api.Delivery

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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