GHSA-mgr7-5782-6jh9 — Umbraco.Headless.Client.N…
GHSA-mgr7-5782-6jh9 is a security vulnerability in Umbraco.Headless.Client.Net. A fix is available for Umbraco.Headless.Client.Net — see the affected versions and patch details below.
The Umbraco Heartcore headless client library uses a vulnerable Refit dependency package
Real-World Exposure
Umbraco.Headless.Client.NetReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Umbraco.Headless.Client.Net | all versions | 1.5.0dotnet add package Umbraco.Headless.Client.Net --version 1.5.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Umbraco.Headless.Client.Net, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Umbraco.Headless.Client.Net to 1.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mgr7-5782-6jh9 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-mgr7-5782-6jh9 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-mgr7-5782-6jh9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-mgr7-5782-6jh9 in your dependencies?
O3 Security finds GHSA-mgr7-5782-6jh9 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.