v37.0.1: Release Wasmtime 37.0.1 (#11738)

37.0.1

Released 2025-09-23.

Fixed

• Cranelift's cranelift-jit crate now properly applies relocations to ADRP
  instructions on aarch64; a zero-extension on the offset was fixed to properly
  sign-extend instead.
  #11734

v37.0.0: Release Wasmtime 37.0.0 (#11724)

37.0.0

Released 2025-09-20.

Added

• Wasmtime now fully implements the WebAssembly exception-handling proposal.
  Support is still disabled by default but is ready for testing. The proposal
  will be enabled by default in a future release of Wasmtime.
  #11326

• An initial implementation of WASIp3 is available for the 0.3.0-rc-2025-08-15
  tag made for the WASIp3 release. Note that this is not production ready yet
  but is an excellent time to start kicking the tires in preparation for an
  upcoming officialy WASIp3 0.3.0 release. Users of the CLI can opt-in with
  -Sp3 -Wcomponent-model-async.
  #11406
  #11423
  #11443

• Wasmtime has initial support for the Linux PAGEMAP_SCAN ioctl which can
  greatly improve instantiation throughput in scenarios with a high number of
  instantiations and short instance lifetime. This support is disabled by
  default but will likely be enabled by default in a future release.
  #11372
  #11433

• GC support can now be configured in Config and not only through crate
  features through Config::gc_support.
  #11463

• Wasmtime now supports reading metrics of the pooling allocator at runtime.
  #11490

• The ManuallyRooted type is now replaced with OwnedRooted which is intended
  to make management of GC object lifetimes on the host easier.
  #11514

• Wasmtime's documentation of the C++ embedding API and examples has been
  expanded.
  #11569

• Wasmtime's support for the stack-switching WebAssembly proposal continues to
  progress on x86_64 Linux.
  #11003

Changed

• The preview0 and preview1 modules and features in the wasmtime-wasi
  crate are now called p0 and p1.
  #11380

• Release artifacts for the C API are now unconditionally built with unwind
  tables.
  #11383

• Wasmtime now requires Rust 1.87.0 or later to build.
  #11396

• The component-model-async gated AbortHandle is now named JoinHandle.
  #11414

• Wasmtime's internal implementation details are now async in many more
  locations to help ensure the implementation is more sound.
  #11411
  #11416
  #11442
  #11444
  #11457
  #11460
  #11461
  #11468
  #11470
  #11481
  #11496

• Component-model-async primitives such as streams, tasks, etc, now use the same
  table as resources in a component. This means that guest-visible allocated
  indices are updated slightly.
  #11374

• Wasmtime's precompiled binaries available from CI now include the
  component-model-async feature.
  #11429

• C API release artifacts are now built with LTO so they have a smaller size.
  #11483

• Code can no longer be loaded on x86_64-unknown-none by default without
  opting-in to a contract that either the host is compiled with SSE2 support or
  wasm is compiled with enough features that libcalls aren't used.
  #11553

• Host support for component model async futures/streams has been updated to a
  new API.
  #11515

Fixed

• GC of dead DWARF has been improved.
  #11402

• Wasm-gc branching instructions now correctly check for fuel.
  #11426

• The array.new_default instruction now checks for fuel/epochs in its inner
  loop.
  #11428

• The "min" C API artifacts now have correct headers.
  #11479

• GC OOM during const eval no longer panics.
  #11557

• Wasmtime now properly respects a disabled std feature even on targets which
  have std available.
  #11568

v36.0.2: Release Wasmtime 36.0.2 (#11541)

36.0.2

Released 2025-08-26.

Fixed

• Wasmtime will no longer panic in the pooling allocator when in near-OOM
  conditions related to resetting the linear memory of a slot.
  #11510

v36.0.1: Release Wasmtime 36.0.1 (#11477)

36.0.1

Released 2025-08-21.

Added

• Accessors for internal WASI-related contexts are added to
  wasmtime_wasi::WasiCtx to account for refactorings that happened in this
  release.
  #11473

Changed

• Release artifacts for the C API are now smaller than the previous release to
  assist with redistribution as-is.
  #11483

v36.0.0: Release Wasmtime 36.0.0 (#11471)

36.0.0

Released 2025-08-20.

Added

• Cranelift's has initial support for inlining between functions. Wasmtime
  additionally now has support for inlining as well, for example between modules
  in a component.
  #11210
  #11239
  #11228
  #11269
  #11283

• The async proposal for the Component Model is now fully implemented in
  Wasmtime with a number of WASIp3 interfaces implemented. The implementation
  is still off-by-default and the implementation of WASIp3 is not fully
  complete, but is remains suitable for testing.
  #11127
  #11136
  #11137
  #11238
  #11221
  #11250
  #11257
  #11291
  #11325

Changed

• Users who implemented WasiHttpView::is_forbidden_header from
  wasmtime-wasi-http now need to include DEFAULT_FORBIDDEN_HEADERS, e.g.
  DEFAULT_FORBIDDEN_HEADERS.contains(name) || name.as_str() == "custom-forbidden-header"
  #11292

• Cranelift's incremental cache has received some optimizations.
  #11186

• Wasmtime's internal implementations of WebAssembly primitives has been
  refactored to be modeled with safer internal primitives.
  #11211
  #11212
  #11216
  #11229
  #11215
  #11254
  #11255
  #11319
  #11320

• Detection of native hardware features has been refactored on s390x.
  #11220

• Further progress has been made towards an implementation of the WebAssembly
  exceptions proposal, although it is not yet complete.
  #11230
  #11321

• Cranelift's assembler for x64 now supports EVEX encoding.
  #11153
  #11270
  #11303

• The default implementation of send_request in the wasmtime-wasi-http crate
  is now behind an on-by-default feature gate.
  #11323

• Configuration of the bindgen! macro has been redesigned to more consistently
  configure per-function options such as whether or not it's async.
  #11328

• Initial support fo mutatis has been added to Wasmtime's fuzzers.
  #11290

• The debug-builtins crate feature of wasmtime no compiles on no_std
  targets.
  #11304

Fixed

• Deserializing external modules no long unnecessarily requires the allocation
  to be aligned.
  #11306

• A CMake linker error and warning when using the C API on macOS has been fixed.
  #11293
  #11315

• The C API declaration of wasmtime_component_linker_instance_add_func has
  been fixed.
  #11327

• The calculation of reachable DWARF has been fixed.
  #11338

v35.0.0: Release Wasmtime 35.0.0 (#11286)

35.0.0

Released 2025-07-22.

Added

• A new InputFile type has been added for specifying stdin as a file in WASI.
  #10968

• Conditional branches to unconditional traps are now translated to conditional
  traps during legalization.
  #10988

• The TE HTTP header can now be specified by guests.
  #11002

• Winch on AArch64 should now pass all WebAssembly MVP tests. Note that it is
  still not yet Tier 1 at this time, however.
  #10829
  #11013
  #11031
  #11051

• The x64 backend now has lowering rules for {add,sub,or,and} mem, imm
  #11043

• Initial support for WASIp2 in the C API has started to land.
  #11055
  #11172

• Initial support for GC support in the component model has started to land
  (note that it is not finished yet).
  #10967
  #11020

• The wasmtime-wasi-nn crate now has a feature to use a custom ONNX runtime.
  #11060

• Cranelift now optimizes division-by-constant operations to no longer use
  division.
  #11129

• A native-tls backend has been added for the wasi-tls implementation.
  #11064

Changed

• Many more instructions for the x64 backend in Cranelift were migrated to the
  new assembler.
  #10927
  #10928
  #10918
  #10946
  #10954
  #10958
  #10971
  #10942
  #10975
  #11017
  #10898
  #10836
  ... (and more)

• Wasmtime internally uses Pin for VM data structures to make the internal
  implementations more sound to use. This has no effect on the public API of
  Wasmtime.
  #10934
  #10937
  #10943
  #10959
  #11042

• Fused adapters between components now transfer the enum component model type
  more efficiently.
  #10939

• Filenames of --emit-clif now match the symbol names found in *.cwasm
  artifacts and include the function name as well.
  #10947
  #11040

• Wasmtime-internal crates are now all named wasmtime-internal-* to even
  further discourage their use.
  #10963

• Codegen of conditional traps with float compares has been improved.
  #10966

• More patterns are now optimized in ISLE mid-end rules.
  #10978
  #10979
  #11173

• Winch's support for constants/scratch registers has been improved internally.
  #10986
  #10998

• The C API artifacts on Windows are now produced with Clang instead of
  cl.exe.
  #10890

• WebAssembly operand types are now taken into account during translation to
  optimize codegen better in the face of subtyping.
  #11030

• The behavior of blocking-write-and-flush has been updated during flushing
  when closed is found.
  #11018

• WASI WITs have been updated to 0.2.6.
  #11049

• OpenVINO has been updated to v2025.1.
  #11054

• The size of the wasmtime.addrmap section in *.cwasm artifacts has been
  shrunk slightly.
  #11126

• Authorities in wasmtime-wasi-http can now contain the : character.
  #11145

• Wasmtime now requires Rust 1.86 to compile.
  #11142

• Wasmtime's DRC collector has been optimized and has a new more efficient means
  of managing the set of over-approximated roots on the stack.
  #11144
  #11148
  #11167
  #11168
  #11169
  #11175

• The ComponentType trait in Wasmtime now requires the Send and Sync
  bounds for all implementors.
  #11160

• The V128 type is now usable on platforms other than aarch64 and x86_64.
  #11165

• Wasmtime's policy on unsafe code and guidelines has been added.
  #11177

• The std crate will no longer implicitly be used on cfg(unix) and
  cfg(windows) targets when the std Cargo feature is disabled. This means
  that these platforms now require std to be enabled to use the
  platform-specific implementation of linear memory, for example.
  #11152

Fixed

• A panic when optimizing icmp with vectors has been fixed.
  #10948

• A panic when lowering scalar_to_vector with i16x8 types has been fixed.
  #10949

• The vector state register is now considered clobbered by calls on riscv64 to
  ensure it's updated across calls.
  #11048

• An instance of gdb crashing on DWARF emitted by Wasmtime has been fixed.
  #11077

• Fix a panic in the host caused by preview1 guests using fd_renumber.
  CVE-2025-53901.

• Fix a panic in the preview1 adapter caused by guests using fd_renumber.
  #11277

v34.0.2: Release Wasmtime 34.0.2 (#11275)

34.0.2

Released 2025-07-18.

Fixed

• Fix a panic in the host caused by preview1 guests using fd_renumber.
  CVE-2025-53901.

• Fix a panic in the preview1 adapter caused by guests using fd_renumber.
  #11277

34.0.1

Released 2025-06-24.

Fixed

• Fix a panic with host-defined tables/globals and concrete reference
  types.
  #11103

v33.0.2: Release Wasmtime 33.0.2 (#11274)

33.0.2

Released 2025-07-18.

Fixed

• Fix a panic in the host caused by preview1 guests using fd_renumber.
  CVE-2025-53901.

• Fix a panic in the preview1 adapter caused by guests using fd_renumber.
  #11277

33.0.1

Released 2025-06-24.

Fixed

• Fix a panic with host-defined tables/globals and concrete reference
  types.
  #11103

v24.0.4: Release Wasmtime 24.0.4 (#11273)

24.0.4

Released 2025-07-18.

Fixed

• Fix a panic in the host caused by preview1 guests using fd_renumber.
  CVE-2025-53901.

• Fix a panic in the preview1 adapter caused by guests using fd_renumber.
  #11277

24.0.3

Released 2025-06-24.

Fixed

• Fix a panic with host-defined tables/globals and concrete reference
  types.
  #11103

v34.0.1: Release Wasmtime 34.0.1 (#11119)

34.0.1

Released 2025-06-24.

Fixed

• Fix a panic with host-defined tables/globals and concrete reference
  types.
  #11103