v45.0.0: Release Wasmtime 45.0.0 (#13416)

45.0.0

Released 2026-05-21.

Added

• Winch now respects the enable_nan_canonicalization setting.
  #12939

• Initial support for invoking component functions asynchronously has been added
  to the C API.
  #12973

• Cranelift's s390x backend implements more instructions from z17 and also
  implements more CLIF arithmetic overflow instructions.
  #12523
  #12707

• Wasmtime's support for handling OOM in more APIs has expanded and is now
  documented as well.
  #12993
  #12988
  #13017
  #13047
  #13049
  #13051
  #13074
  #13083
  #13088
  #13224

• The Component type now offers reflection APIs over the compiled in-memory
  view of instructions in the same manner Module does.
  #13073

• The wasmtime CLI now has a hot-blocks subcommand to explore a
  perf-recorded output and show hot basic blocks of WebAssembly instructions.
  #13077

• Wasmtime now has an initial implementation of a copying collector for GC,
  which notably enables collecting cycles unlike the DRC collector.
  #13093
  #13107

• The WASI inherit_network and allow_ip_name_lookup options were added to
  the C API.
  #13145

• The C API now has the ability to select Winch as well as the
  RegallocAlgorithm in use.
  #13155

• The Wasmtime CLI now has a -Dmax-backtrace=N argument to control the number
  of frames captured.
  #13218

• Wasmtime now tracks whether there are any active async tasks within a store
  and provides an embedder API to learn when there are none left.
  #13246

• Cranelift now has an idempotent-store elimination pass.
  #13251

Changed

• Wasmtime's DRC collector has received some optimizations to get some wins on
  local benchmarking.
  #12969
  #12974

• Wasmtime's C API can now be built without the gc crate feature of Wasmtime.
  #12805

• Wasmtime now has an implemented and improved grow-vs-collect heuristic to
  improve behavior of GC-using programs.
  #12942

• Cranelift on aarch64 now uses a more optimized frame layout for tail-call-only
  functions.
  #11608

• Wasmtime now supports a separate set of GC tunables different from the main
  set of tunables for linear memory to enable configuring it separately.
  #13080

• Wasmtime no longer uses pointer authentication instructions for the
  implementation of fibers due to issues on Android.
  #13118

• Wasmtime now requires Rust 1.93.0 to compile.
  #13127

• The behavior of using Wasmtime as a CMake subproject has been improved.
  #13157

• Reference types in the C/C++ API have been refactored and reorganized.
  #13154
  #13235

• The Wasmtime CLI now warns about usage of wasi-common or wasi-threads as these
  components are slated for removal in Wasmtime 47.0.0. For more information see
  the associated RFC.
  #13264

• Inlining in Wasmtime now has a different set of configuration options, notably
  more values are packed into -Cinlining=....
  #13250

Fixed

• The WASIp1-to-WASIp2 adapter now handles nonblocking I/O in fd_{read,write}
  more appropriately.
  #13111

• The Host header is injected less often for wasmtime-wasi-http.
  #13138

• Downcasts of funcref values now uses the correct type for imported
  functions.
  #13161

• The DRC allocator's memory usage during tracing has been reduced when there
  are large arrays.
  #13192

• The performance of reading stdin in WASI has been improved.
  #13256

• WASI path_open(TRUNCATE) bypasses FilePerms::WRITE host restriction.
  GHSA-2r75-cxrj-cmph

v44.0.2: Release Wasmtime 44.0.2 (#13436)

44.0.2

Released 2026-05-21.

Fixed

• WASI path_open(TRUNCATE) bypasses FilePerms::WRITE host restriction.
  GHSA-2r75-cxrj-cmph

v36.0.10: Release Wasmtime 36.0.10 (#13435)

36.0.10

Released 2026-05-21.

Fixed

• WASI path_open(TRUNCATE) bypasses FilePerms::WRITE host restriction.
  GHSA-2r75-cxrj-cmph

v24.0.9: Release Wasmtime 24.0.9 (#13434)

24.0.9

Released 2026-05-21.

Fixed

• WASI path_open(TRUNCATE) bypasses FilePerms::WRITE host restriction.
  GHSA-2r75-cxrj-cmph

dev

Trigger GC in the DRC collector when the OASR list is twice the size …

v36.0.9: Release Wasmtime 36.0.9 (#13276)

36.0.9

Released 2026-05-05.

Fixed

• Cranelift's timing infrastructure is now more robust in the face of buggy system clocks.
  #12709
  #13253

v44.0.1: Release Wasmtime 44.0.1 (#13241)

44.0.1

Released 2026-04-30.

Fixed

• Panic when allocating a table exceeding the size of the host's address space.
  GHSA-p8xm-42r7-89xg

v43.0.2: Release Wasmtime 43.0.2 (#13240)

43.0.2

Released 2026-04-30.

Fixed

• Panic when allocating a table exceeding the size of the host's address space.
  GHSA-p8xm-42r7-89xg

v36.0.8: Release Wasmtime 36.0.8 (#13239)

36.0.8

Released 2026-04-30.

Fixed

• Panic when allocating a table exceeding the size of the host's address space.
  GHSA-p8xm-42r7-89xg

v24.0.8: Release Wasmtime 24.0.8 (#13238)

24.0.8

Released 2026-04-30.

Fixed

• Fixed a bug in lowering of f64.copysign on x86-64 whereby when combined
  with an f64.load, the resulting machine code could read 16 bytes rather
  than 8 bytes. This could result in a segfault when Wasmtime is configured
  without signals-based traps.
  GHSA-vc8c-j3xm-xj73