The Umbraco Heartcore headless client library uses a vulnerable Refit dependency package

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact The Heartcore headless client library depends on Refit to assist in making HTTP requests to Heartcore public APIs. Refit recently published an advisory regarding a CRLF injection vulnerability whereby it is possible for a malicious user to smuggle additional headers or potentially body content into a request. This shouldn't affect Heartcore client library usage as the vulnerable method - HttpHeaders.TryAddWithoutValidation - is not used. However, since Refit is a transient dependency for applications using this library, then any users making direct use of Refit could be vulnerable. Patches The vulnerable version of Refit has been upgraded to a secure version, as of Umbraco.Headless.Client.Net version 1.5.0, available on Nuget. Workarounds If calling Refit from your own code, set any necessary HTTP headers without use of HttpHeaders.TryAddWithoutValidation. References See the original Refit advisory for further info.

Published by the source

13 Jan 2025, 16:18 UTC

Last modified by the source

13 Jan 2025, 16:18 UTC

Source last checked

26 Oct 2026, 17:03 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-mgr7-5782-6jh9

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# Patch Next advisory brief: GHSA-mgr7-5782-6jh9

Advisory: The Umbraco Heartcore headless client library uses a vulnerable Refit dependency package
IDs: GHSA-mgr7-5782-6jh9
Record: https://patchnext.com/advisories/ghsa-mgr7-5782-6jh9 (revision 1, source checked 26 Oct 2026, 17:03 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: umbraco.headless.client.net 1.5.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet umbraco.headless.client.net: affected <= 1.4.1; fixed in 1.5.0

## Suggested inspection (read-only)
- NuGet umbraco.headless.client.net: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on umbraco.headless.client.net.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-mgr7-5782-6jh9 (GitHub-reviewed advisory GHSA-mgr7-5782-6jh9 lists affected ranges: NuGet umbraco.headless.client.net >=0 <=1.4.1)

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