# GHSA-8fh9-c4jq-94h4: idunno.Bluesky, idunno.AtProto and idunno.AtProto.OAuthCallback Denial of Service Vulnerability > A denial of service vulnerability in a transitive dependency affects Bluesky and AtProto libraries, requiring an upgrade to resolve. - **Severity:** Not scored - **Exploited in the wild:** Not known - **Login needed:** Not stated - **Attackable:** Over the internet - **Victim action needed:** Not stated - **Fix available:** Yes - **Published:** 13 Mar 2026 ## What is GHSA-8fh9-c4jq-94h4? GHSA-8fh9-c4jq-94h4 is a denial of service vulnerability in idunno.AtProto, published on 13 Mar 2026. It can be exploited over the network. ### Official 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](https://github.com/dotnet/announcements/issues/384) ## 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. * To update a specific package to its latest version, use the following add package command: * If you are using `idunno.Bluesky` `dotnet package update idunno.Bluesky` * If you are using `idunno.AtProto` as a direct dependency `dotnet package update idunno.AtProto` * If you are using `idunno.AtProto.OAuthCallback` as a direct dependency `dotnet package update idunno.AtProto.OAuthCallback` ### Using the NuGet Package Manager Console in Visual Studio: * Open your project in Visual Studio. * Navigate to "Tools > NuGet Package Manager > Package Manager Console". * To update a specific package to its latest version, use the following Update-Package command: * If you are using `idunno.Bluesky` `Update-Package -Id idunno.Bluesky` * If you are using `idunno.AtProto` as a direct dependency `Update-Package -Id idunno.AtProto` * If you are using `idunno.AtProto.OAuthCallback` as a direct dependency `Update-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 * [Microsoft Security Advisory CVE-2026-26127 – .NET Denial of Service Vulnerability](https://github.com/dotnet/announcements/issues/384) * [CVE-2026-26127](https://www.cve.org/CVERecord?id=CVE-2026-26127) ## Which versions are affected by GHSA-8fh9-c4jq-94h4? 6 open source packages ship an affected version, including idunno.AtProto, idunno.AtProto.OAuthCallback and idunno.Bluesky. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `idunno.AtProto` | NuGet | All versions | 1.7.0 | | `idunno.AtProto` | NuGet | All versions | 1.7.0 | | `idunno.AtProto.OAuthCallback` | NuGet | All versions | 1.7.0 | | `idunno.AtProto.OAuthCallback` | NuGet | All versions | 1.7.0 | | `idunno.Bluesky` | NuGet | All versions | 1.7.0 | | `idunno.Bluesky` | NuGet | All versions | 1.7.0 | ## How do I fix GHSA-8fh9-c4jq-94h4? Upgrade idunno.AtProto to 1.7.0 or later. ## Is GHSA-8fh9-c4jq-94h4 being exploited? There is no known exploitation of GHSA-8fh9-c4jq-94h4 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for GHSA-8fh9-c4jq-94h4 and fix it if it is affected. What it is: GHSA-8fh9-c4jq-94h4 is a denial of service vulnerability in idunno.AtProto, published on 13 Mar 2026. It can be exploited over the network. Exploitation: There is no known exploitation of GHSA-8fh9-c4jq-94h4 in the wild and no public exploit code. Affected packages and fixed versions: - idunno.AtProto (NuGet): affected all versions; fixed in 1.7.0 - idunno.AtProto (NuGet): affected all versions; fixed in 1.7.0 - idunno.AtProto.OAuthCallback (NuGet): affected all versions; fixed in 1.7.0 - idunno.AtProto.OAuthCallback (NuGet): affected all versions; fixed in 1.7.0 - idunno.Bluesky (NuGet): affected all versions; fixed in 1.7.0 - idunno.Bluesky (NuGet): affected all versions; fixed in 1.7.0 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/GHSA-8fh9-c4jq-94h4/ (Markdown: https://insights.sbomify.com/GHSA-8fh9-c4jq-94h4/index.md) ``` ## Sources - OSV: https://osv.dev/vulnerability/GHSA-8fh9-c4jq-94h4 --- From sbomify Insights: https://insights.sbomify.com/GHSA-8fh9-c4jq-94h4/ Summaries are generated and may contain mistakes; the official description above is the record.