Issues

• JIT: Incorrect displacement for VPMULUDQ with embedded broadcast

  area-CodeGen-coreclruntriaged
  dotnet/runtime#135844 · Filter by author HMBSbige opened on Oct 15, 2026
  1

• QuicStreamTests.ReadsClosedFinishes test failure in CI

  area-System.Net.Quicblocking-clean-ciKnown Build Erroruntriaged
  dotnet/runtime#135843 · Filter by author jkotas opened on Oct 15, 2026
  1

• Unix enumeration returns "." and ".." as FileInfo when readdir reports DT_REG, despite ReturnSpecialDirectories=false

  area-System.IOuntriaged
  dotnet/runtime#135832 · Filter by author systemparadoxical opened on Oct 15, 2026
  1

• Proposal: Unique, reversable name mangling / sanitization for ilc and crossgen2 symbols

  area-NativeAOT-coreclrarea-ReadyToRun
  dotnet/runtime#135831 · Filter by author jtschuster opened on Oct 15, 2026
  8

• Portable thread pool: Unregister(null) after a one-shot wait fired leaks an AutoResetEvent (Ping.SendPingAsync leaks a handle per ping)

  area-System.Threadinguntriaged
  dotnet/runtime#135824 · Filter by author qiyinxi opened on Oct 14, 2026
  1

• JIT: (bug) [Tier0] ArgumentNullException.ThrowIfNull(r.Ref) on a null byref no longer throws NullReferenceException

  area-CodeGen-coreclr
  dotnet/runtime#135822 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

  

• JIT: (bug) crash (null deref in impFixPredLists) for finally { while (true) {} } when profile weights are used

  area-CodeGen-coreclr
  dotnet/runtime#135819 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

  

• JIT: (bug) OSR patchpoint is not placed for a loop whose backedge-source block has a non-empty IL stack (e.g. while (i < (flag ? a : b))), so the loop stays in Tier0 (~100x slower)

  area-CodeGen-coreclr
  dotnet/runtime#135818 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

  

• JIT: (bug) impImportAndPushBoxForNullable drops GTF_IND_INITCLASS, allowing Nullable<T> loads to be hoisted before static constructor

  area-CodeGen-coreclr
  dotnet/runtime#135817 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

  

• JIT: (bug) signed int.Log2(x) expansion throws before earlier operands are evaluated (wrong exception order, skipped side effect)

  area-CodeGen-coreclr
  dotnet/runtime#135816 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

  

• JIT: (bug) OptimizeBools merges x < 0 || v.GetElement(x) < 0 and speculates a GetElement whose bounds check was removed

  area-CodeGen-coreclr
  dotnet/runtime#135815 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

• JIT: (bug) int.RotateLeft/RotateRight constant folding creates a non-sign-extended TYP_INT constant, so comparisons against it are folded to the wrong result

  area-CodeGen-coreclr
  dotnet/runtime#135814 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

  

• JIT: (bug) PHI-based jump threading leaves stale VNs on the parents of rewritten PHI uses, so CSE reuses a value from a different SSA def

  area-CodeGen-coreclr
  dotnet/runtime#135813 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

• JIT: (bug) RBO jump threading leaves stale PHI SSA that strength reduction treats as loop-invariant (wrong result)

  area-CodeGen-coreclr
  dotnet/runtime#135812 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

• JIT: (bug) redundant branch opts remove a null check that a non-faulting load depends on (spurious NullReferenceException)

  area-CodeGen-coreclr
  dotnet/runtime#135811 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

• JIT: (bug) optJumpThreadCore omits target PHI args for threaded edges, causing RangeCheck to unsoundly eliminate bounds checks

  area-CodeGen-coreclr
  dotnet/runtime#135810 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

• JIT: (bug) tuple swap of struct locals with a class-init static struct field reads the new value

  area-CodeGen-coreclr
  dotnet/runtime#135809 · Filter by author EgorBo opened on Oct 14, 2026 · 12.0.0
  1

• Improve Brotli compression of Wasm ReadyToRun runtime-function tables without eager startup reconstruction

  area-ReadyToRuntenet-performanceuntriaged
  dotnet/runtime#135796 · Filter by author davidwrighton opened on Oct 14, 2026
  1

• HighNumberedFd_NotLeakedAfterLoweringRLimit test failing in CI

  area-System.Diagnostics.Processblocking-clean-ciKnown Build Erroruntriaged
  dotnet/runtime#135795 · Filter by author jkotas opened on Oct 14, 2026
  3

• GC: a ≥ 4 GB array allocated during a background GC can contain a stray 0x01 byte (PREV_EMPTY left by make_unused_array)

  area-GC-coreclr
  dotnet/runtime#135791 · Filter by author kforge-labs-io opened on Oct 14, 2026 · 10.0.x
  1

• OSSupportTest.IOControl_SIOCATMARK_Unix_Success does not wait for the out-of-band byte

  area-System.Net.Socketstest-bug
  dotnet/runtime#135787 · Filter by author caraioniurie47 opened on Oct 14, 2026 · Future
  2

• [Test Failure] Http1ResponseStreamZeroByteReadTest.ZeroByteRead_BlocksUntilDataIsAvailable on Android x64 CoreCLR

  area-System.Net.Httpblocking-clean-ciKnown Build Erroros-androiduntriaged
  dotnet/runtime#135782 · Filter by author ViveliDuCh opened on Oct 14, 2026
  2

• Add support for HPKE in COSE

  area-System.Security
  Feature

  dotnet/runtime#135781 · Filter by author bartonjs opened on Oct 14, 2026 · Future
  2

• [mono][aot] AOT compiler output differs between runs with byte-identical inputs even with the deterministic option (differences beyond the AOTID), android-arm64 and android-x64

  area-Codegen-AOT-monountriaged
  dotnet/runtime#135770 · Filter by author jrramosdominguez opened on Oct 14, 2026
  1

• Linux: HMAC instance creation/disposal regressed 29–33% between .NET 11 preview 4 and RC2

  area-System.Securitytenet-performance
  dotnet/runtime#135759 · Filter by author DeagleGross opened on Oct 14, 2026 · Future
  4