CI failure on Windows: Connection aborted in SocketsHttpHandler_HttpClientHandlerTest.SendAsync_RequestWithLatin1HeaderValue_Succeeds

[svick]

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1542869
Build error leg or test failing: System.Net.Http.Functional.Tests.SocketsHttpHandler_HttpClientHandlerTest.SendAsync_RequestWithLatin1HeaderValue_Succeeds
Pull request: https://github.com/dotnet/runtime.git/pull/131876

Error Message

DO NOT USE JSON BELOW IF THIS IS A BUILD BREAK otherwise build analysis will allow pull requests to merge that break the build worse. For a build break, do not use this issue form. Make a regular new issue.

Fill the error message using step by step known issues guidance.

{
  "ErrorMessage": ["SocketsHttpHandler_HttpClientHandlerTest.SendAsync_RequestWithLatin1HeaderValue_Succeeds", "SocketException : An established connection was aborted by the software in your host machine."],
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

    System.Net.Http.Functional.Tests.SocketsHttpHandler_HttpClientHandlerTest.SendAsync_RequestWithLatin1HeaderValue_Succeeds(safeChar: 0x007f, headerType: Content) [FAIL]
      System.Net.Http.HttpRequestException : An error occurred while sending the request.
      ---- System.IO.IOException : Unable to read data from the transport connection: An established connection was aborted by the software in your host machine..
      -------- System.Net.Sockets.SocketException : An established connection was aborted by the software in your host machine.
      Stack Trace:
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnection.cs(902,0): at System.Net.Http.HttpConnection.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
        /_/src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs(725,0): at System.Runtime.CompilerServices.AsyncHelpers.TransparentAwait[T](Task`1 task)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/ConnectionPool/HttpConnectionPool.cs(389,0): at System.Net.Http.HttpConnectionPool.SendWithNtConnectionAuthAsync(HttpConnection connection, HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/ConnectionPool/HttpConnectionPool.cs(501,0): at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
        /_/src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/RuntimeAsyncTaskContinuation.cs(139,0): at System.Runtime.CompilerServices.RuntimeAsyncTaskContinuation.GetResult[T](Task task, Byte& result)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/RedirectHandler.cs(29,0): at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpMessageHandlerStage.cs(21,0): at System.Net.Http.HttpMessageHandlerStage.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/SocketsHttpHandler.cs(668,0): at System.Net.Http.SocketsHttpHandler.<SendAsync>g__CreateHandlerAndSendAsync|119_0(HttpRequestMessage request, CancellationToken cancellationToken)
        /_/src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/RuntimeAsyncTaskContinuation.cs(139,0): at System.Runtime.CompilerServices.RuntimeAsyncTaskContinuation.GetResult[T](Task task, Byte& result)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/HttpClient.cs(544,0): at System.Net.Http.HttpClient.<SendAsync>g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)
        /_/src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/RuntimeAsyncTaskContinuation.cs(139,0): at System.Runtime.CompilerServices.RuntimeAsyncTaskContinuation.GetResult[T](Task task, Byte& result)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/HttpClient.cs(518,0): at System.Net.Http.HttpClient.SendAsync(HttpRequestMessage request)
        /_/src/libraries/Common/tests/System/Net/Http/HttpClientHandlerTest.cs(2276,0): at System.Net.Http.Functional.Tests.HttpClientHandlerTest.<>c__DisplayClass54_0.<SendAsync_RequestWithLatin1HeaderValue_Succeeds>b__0(Uri uri)
        /_/src/libraries/Common/tests/System/Threading/Tasks/TaskTimeoutExtensions.cs(119,0): at System.Threading.Tasks.TaskTimeoutExtensions.GetRealException(Task task)
        --- End of stack trace from previous location ---
        /_/src/libraries/Common/tests/System/Threading/Tasks/TaskTimeoutExtensions.cs(89,0): at System.Threading.Tasks.TaskTimeoutExtensions.WhenAllOrAnyFailed(Task[] tasks)
        /_/src/libraries/Common/tests/System/Net/Http/GenericLoopbackServer.cs(44,0): at System.Net.Test.Common.LoopbackServerFactory.<>c__DisplayClass6_0.<CreateClientAndServerAsync>b__0(GenericLoopbackServer server, Uri uri)
        /_/src/libraries/Common/tests/System/Net/Http/LoopbackServer.cs(107,0): at System.Net.Test.Common.LoopbackServer.CreateServerAsync(Func`2 funcAsync, Options options)
        /_/src/libraries/Common/tests/System/Net/Http/HttpClientHandlerTest.cs(2251,0): at System.Net.Http.Functional.Tests.HttpClientHandlerTest.SendAsync_RequestWithLatin1HeaderValue_Succeeds(Char safeChar, HeaderType headerType)
        --- End of stack trace from previous location ---
        ----- Inner Stack Trace -----
        /_/src/coreclr/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncHelpers.CoreCLR.cs(739,0): at System.Runtime.CompilerServices.AsyncHelpers.TransparentAwait[T](ValueTask`1 task)
        /_/src/libraries/System.Net.Sockets/src/System/Net/Sockets/NetworkStream.cs(607,0): at System.Net.Sockets.NetworkStream.ReadAsync(Memory`1 buffer, CancellationToken cancellationToken)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnection.cs(1655,0): at System.Net.Http.HttpConnection.InitialFillAsync(Boolean async)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnection.cs(650,0): at System.Net.Http.HttpConnection.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
        ----- Inner Stack Trace -----
        /_/src/libraries/System.Net.Sockets/src/System/Net/Sockets/Socket.Tasks.cs(1374,0): at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.CreateException(SocketError error, Boolean forAsyncThrow)
        /_/src/libraries/System.Net.Sockets/src/System/Net/Sockets/Socket.Tasks.cs(1056,0): at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ReceiveAsync(Socket socket, CancellationToken cancellationToken)
        /_/src/libraries/System.Net.Sockets/src/System/Net/Sockets/Socket.Tasks.cs(305,0): at System.Net.Sockets.Socket.ReceiveAsync(Memory`1 buffer, SocketFlags socketFlags, Boolean fromNetworkStream, CancellationToken cancellationToken)
        /_/src/libraries/System.Net.Sockets/src/System/Net/Sockets/NetworkStream.cs(597,0): at System.Net.Sockets.NetworkStream.ReadAsync(Memory`1 buffer, CancellationToken cancellationToken)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnection.cs(1655,0): at System.Net.Http.HttpConnection.InitialFillAsync(Boolean async)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnection.cs(650,0): at System.Net.Http.HttpConnection.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/ConnectionPool/HttpConnectionPool.cs(398,0): at System.Net.Http.HttpConnectionPool.SendWithNtProxyAuthAsync(HttpConnection connection, HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/ConnectionPool/HttpConnectionPool.cs(388,0): at System.Net.Http.HttpConnectionPool.SendWithNtConnectionAuthAsync(HttpConnection connection, HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
        /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/ConnectionPool/HttpConnectionPool.cs(501,0): at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
        /_/src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/Task.cs(3636,0): at System.Threading.Tasks.Task.RunContinuations(Object continuationObject)
        /_/src/libraries/System.Private.CoreLib/src/System/Threading/ThreadPoolWorkQueue.cs(960,0): at System.Threading.ThreadPoolWorkQueue.Dispatch()
        /_/src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.WorkerThread.cs(137,0): at System.Threading.PortableThreadPool.WorkerThread.WorkerDoWork(PortableThreadPool threadPoolInstance)
        /_/src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.WorkerThread.cs(110,0): at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart()
        /_/src/coreclr/System.Private.CoreLib/src/System/Threading/Thread.CoreCLR.cs(117,0): at System.Threading.Thread.StartCallback(Thread* pThread)
        --- End of stack trace from previous location ---

This is similar to #130458

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1542869
Error message validated: [SocketsHttpHandler_HttpClientHandlerTest.SendAsync_RequestWithLatin1HeaderValue_Succeeds SocketException : An established connection was aborted by the software in your host machine.]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 8/7/2026 1:52:53 PM UTC

Report

Build	Repository	Test	Pull Request
1542869	dotnet/runtime	System.Net.Http.Functional.Tests.SocketsHttpHandler_HttpClientHandlerTest.SendAsync_RequestWithLatin1HeaderValue_Succeeds	#131876

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	1	1

[dotnet-policy-service]

Tagging subscribers to this area: @karelz, @dotnet/ncl
See info in area-owners.md if you want to be subscribed.