Issues

• [API Proposal]: Add direct IBufferWriter<byte> output support to CborWriter similar to Utf8JsonWriter style

  api-suggestionarea-System.IOuntriaged
  dotnet/runtime#136164 · Filter by author sichanyoo opened on Oct 20, 2026
  1

• Http3 tests failing with "An error occurred while sending the request."

  area-System.Net.Httpblocking-clean-ciKnown Build Erroruntriaged
  dotnet/runtime#136162 · Filter by author jkotas opened on Oct 20, 2026
  1

• [API Proposal]: Optional .env configuration provider

  area-Extensions-Configurationuntriaged
  dotnet/runtime#136158 · Filter by author vladimir-aubrecht opened on Oct 20, 2026
  1

• "Illegal instruction: Attempted to execute an instruction code not defined by the processor" on stepping when debugger runs macOS ARM and debuggee is from Linux Amd64 docker container

  area-Diagnostics-coreclruntriaged
  dotnet/runtime#136157 · Filter by author eterekhin opened on Oct 20, 2026
  3

• [mono] MetadataUpdater.IsSupported is always false, so Blazor Hybrid hot reload doesn't work on iOS

  area-EnC-monountriaged
  dotnet/runtime#136155 · Filter by author sander1095 opened on Oct 20, 2026

• [ci-scan] Test failure: Runtime_115979 asserts in ValidateInner on WASI R2R

  arch-wasmarea-ReadyToRunblocking-clean-ciKnown Build Erroros-wasiuntriaged
  dotnet/runtime#136153 · Filter by author EgorBo opened on Oct 20, 2026
  2

• [wasm][mono] GC heap blocks take twice their size in linear memory (one posix_memalign per 16 KB block)

  area-GC-monountriaged
  dotnet/runtime#136152 · Filter by author mikernet opened on Oct 20, 2026
  1

• [browser] HotReload functional test is built but not submitted to Helix in CI

  arch-wasmarea-VM-meta-monountriaged
  dotnet/runtime#136150 · Filter by author vitek-karas opened on Oct 20, 2026
  1

• [API Proposal]: Ascii.StartsWith and Ascii.EndsWith for bytes and chars

  api-suggestionarea-System.Memoryuntriaged
  dotnet/runtime#136144 · Filter by author SkyDevLab opened on Oct 20, 2026
  2

• ILVerify reports BadTypeSpec for every unmanaged-constrained generic since #129118

  area-TypeSystem-coreclruntriaged
  dotnet/runtime#136142 · Filter by author pcshrosbree opened on Oct 20, 2026

• [API Proposal]: MemoryExtensions.TrySplit for 2-Way Delimiter Parsing

  api-suggestionarea-System.Memoryuntriaged
  dotnet/runtime#136141 · Filter by author SkyDevLab opened on Oct 20, 2026
  4

• COM IDispatch property setters throw COMException (0x80020005) starting from .NET 11 Preview 4

  area-Interop-coreclruntriaged
  dotnet/runtime#136137 · Filter by author Psyk0loge opened on Oct 20, 2026
  1

• [API Proposal]: ToUpper/LowerAscii helpers for char/string

  api-suggestionarea-System.Runtimeuntriaged
  dotnet/runtime#136134 · Filter by author huoyaoyuan opened on Oct 20, 2026
  1

• .NET 10 JIT miscompile: Avx.AndNot(Avx.Compare(...), x)

  area-CodeGen-coreclr
  dotnet/runtime#136130 · Filter by author ryankelley-lm opened on Oct 20, 2026
  7

  

• Clarify local-variable grammar and encoded type-token scope in Ecma-335-Augments

  area-TypeSystem-coreclruntriaged
  dotnet/runtime#136127 · Filter by author iskiselev opened on Oct 20, 2026
  1

• Test failure: System.Net.Security.Tests.TlsSessionTests.ServerSession_ExternalValidation_PreservesClientCertificateChain intermittently misses the peer intermediate on Windows x86

  area-System.Net.Securityblocking-clean-ciKnown Build Erroruntriaged
  dotnet/runtime#136121 · Filter by author lewing opened on Oct 20, 2026
  1

• Casting a second COM RCW to IEnumerator throws NullReferenceException in __ComObject.IEnumeratorOverEnumVARIANTImpl.MoveNext

  area-System.Runtime.InteropServices
  dotnet/runtime#136118 · Filter by author yudomsft opened on Oct 20, 2026

• JsonArray: concurrent first access can return child nodes that are not in the array

  area-System.Threadinguntriaged
  dotnet/runtime#136117 · Filter by author asylkhan-azat opened on Oct 20, 2026
  1

• ILVerify: verify methods that use calli, mkrefany, refanyval, refanytype or arglist instead of aborting them

  area-CodeGen-coreclrarea-Tools-ILVerificationuntriaged
  dotnet/runtime#136111 · Filter by author pcshrosbree opened on Oct 19, 2026
  4

• FileSystemWatcher leaks a hung background thread on Linux if the watched directory is deleted

  area-System.IOuntriaged
  dotnet/runtime#136103 · Filter by author kg-unity3d opened on Oct 19, 2026
  1

• NativeAOT MethodInvoker.Invoke(object, Span<object>) throws InvalidOperationException instead of TargetParameterCountException for a wrong argument count on an open generic method

  area-NativeAOT-coreclruntriaged
  dotnet/runtime#136102 · Filter by author caraioniurie47 opened on Oct 19, 2026
  1

  

• NativeAOT CreateDelegate fails differently from CoreCLR on a generic method definition or a method of an open generic type

  area-NativeAOT-coreclruntriaged
  dotnet/runtime#136099 · Filter by author caraioniurie47 opened on Oct 19, 2026
  1

• Delegate.CreateDelegate(..., string method, ignoreCase: true, ...) behaves differently on CoreCLR, NativeAOT and Mono when two method names differ only in case

  area-NativeAOT-coreclruntriaged
  dotnet/runtime#136098 · Filter by author caraioniurie47 opened on Oct 19, 2026
  1

• [Mono] Delegate closed over the first argument of a static virtual interface method aborts the process or binds the implementing class's method

  area-VM-meta-monountriaged
  dotnet/runtime#136097 · Filter by author caraioniurie47 opened on Oct 19, 2026

• AcceptWithDefaultValidation_CertificateContextTrust_HonorsChainPolicy test fails with TimeoutException

  area-System.Net.Securityblocking-clean-ciKnown Build Erroruntriaged
  dotnet/runtime#136096 · Filter by author jkotas opened on Oct 19, 2026
  1