GHSA-8fh9-c4jq-94h4
HIGHidunno.Bluesky, idunno.AtProto and idunno.AtProto.OAuthCallback Denial of Service Vulnerability
Blast Radius
idunno.AtProto.NETidunno.AtProto.OAuthCallback.NETidunno.BlueskyReal-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
idunno.Bluesky, idunno.AtProto and idunno.AtProto.OAuthCallback Denial of Service Vulnerability
Impact
The Microsoft.Bcl.Memory package, a transitive dependency of idunno.AtProto and idunno.AtProto.OAuthCallback had a Denial of Service security vulnerability, CVE-2026-26127
Patches
v1.7.0 updates the dependencies on Duende.IdentityModel.OidcClient and Duende.IdentityModel.OidcClient.Extensions which, in turn, updates their dependency on Microsoft.Bcl.Memory to 10.0.4, resolving the vulnerability.
Workarounds
No workarounds exist for this vulnerability.
How to fix the issue
To update your dependencies on idunno.Bluesky, idunno.AtProto and idunno.AtProto.OAuthCallback,
Using the .NET CLI (Command Line Interface):
-
Open a terminal or command prompt in your project's directory.
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To update a specific package to its latest version, use the following add package command:
-
If you are using
idunno.Blueskydotnet package update idunno.Bluesky -
If you are using
idunno.AtProtoas a direct dependencydotnet package update idunno.AtProto -
If you are using
idunno.AtProto.OAuthCallbackas a direct dependencydotnet package update idunno.AtProto.OAuthCallback
-
Using the NuGet Package Manager Console in Visual Studio:
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Open your project in Visual Studio.
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Navigate to "Tools > NuGet Package Manager > Package Manager Console".
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To update a specific package to its latest version, use the following Update-Package command:
-
If you are using
idunno.BlueskyUpdate-Package -Id idunno.Bluesky -
If you are using
idunno.AtProtoas a direct dependencyUpdate-Package -Id idunno.AtProto -
If you are using
idunno.AtProto.OAuthCallbackas a direct dependencyUpdate-Package -Id idunno.AtProto.OAuthCallback
-
NuGet Package Manager UI in Visual Studio:
- Open your project in Visual Studio.
- Right-click on your project in Solution Explorer and select "Manage NuGet Packages..." or navigate to "Project > Manage NuGet Packages".
- In the NuGet Package Manager window, select the "Updates" tab. This tab lists packages with available updates from your configured package sources.
- Select the package(s) you wish to update. You can choose a specific version from the dropdown or update to the latest available version.
- Click the "Update" button.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | idunno.AtProto | all versions | 1.7.0 |
| .NETNuGet | idunno.AtProto.OAuthCallback | all versions | 1.7.0 |
| .NETNuGet | idunno.Bluesky | all versions | 1.7.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for idunno.AtProto. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update idunno.AtProto to 1.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8fh9-c4jq-94h4 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 pinpoints whether GHSA-8fh9-c4jq-94h4 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-8fh9-c4jq-94h4. 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-8fh9-c4jq-94h4 in your dependencies?
O3 detects GHSA-8fh9-c4jq-94h4 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.