## 42.0.1
Released 2026-02-25.
### Fixed
* Fix some minor `bindgen!` issues with `anyhow: true`
[#12658](https://github.com/bytecodealliance/wasmtime/pull/12658)
--------------------------------------------------------------------------------
## 42.0.0
Released 2026-02-24.
### Added
* Cranelift now supports bitwise operations on floats on aarch64.
[#12326](https://github.com/bytecodealliance/wasmtime/pull/12326)
* Cranelift now supports NaN canonicalization of f16 and f128.
[#12337](https://github.com/bytecodealliance/wasmtime/pull/12337)
* Wasmtime has gained minimal support to implement fixed-length lists in the
component model being communicated between composed components.
[#10619](https://github.com/bytecodealliance/wasmtime/pull/10619)
* Wasmtime's `Error` and `Result` types are now built-in to the `wasmtime` crate
and are no longer defined by the `anyhow` crate. Wasmtime exports a
mostly-compatible `anyhow`-like API at `wasmtime::error` which is used
instead. Wasmtime's own `Error` handles OOM internally and is foundational
part of Wasmtime's work-in-progress support to gracefully handle OOM.
[#12309](https://github.com/bytecodealliance/wasmtime/pull/12309)
* Wasmtime now exports an extension trait to convert `anyhow::Result<T>` into
`wasmtime::Result<T>`.
[#12255](https://github.com/bytecodealliance/wasmtime/pull/12255)
* Wasmtime supports a new `bindgen!` option to generate bindings specifically
with `anyhow::Result` instead of `wasmtime::Result`.
[#12331](https://github.com/bytecodealliance/wasmtime/pull/12331)
* The Nvidia-Cuda execution provider is now supported for the wasi-nn onnx
backend.
[#12044](https://github.com/bytecodealliance/wasmtime/pull/12044)
* Non-exported and private entities can now be accessed through the debugger
API.
[#12367](https://github.com/bytecodealliance/wasmtime/pull/12367)
* A new `Store::try_new` API has been added which handles OOM.
[#12415](https://github.com/bytecodealliance/wasmtime/pull/12415)
* Initial configuration knobs for record-and-replay support have been added.
[#12375](https://github.com/bytecodealliance/wasmtime/pull/12375)
* Cranelift's s390x backend now has support for instructions added in z17.
[#12319](https://github.com/bytecodealliance/wasmtime/pull/12319)
* Wasmtime's implementation of fibers can now be compiled on riscv32imac
platforms.
[#12506](https://github.com/bytecodealliance/wasmtime/pull/12506)
* Wasmtime's implementation of WASI now correctly limits resource consumption on
behalf of the guest, such as host-allocated memory, by default. This means
that some behaviors previously allowed by Wasmtime are now disallowed by
default if they rely on transferring a large amount of data from the guest to
the host. Additionally calls to `wasi:random/random.get-random-bytes`, for
example, now have limits in place by default to avoid allocating too much
memory on the host. For more information on this see the related security
advisory with further details on knobs added and what behaviors are now
restricted by default.
[GHSA-852m-cvvp-9p4w](https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-852m-cvvp-9p4w)
### Changed
* Reentrance rules for WebAssembly components have changed in accordance with
upstream specification changes. Embeddings are not expected to be affected,
but please reach out if you find problems.
[#12349](https://github.com/bytecodealliance/wasmtime/pull/12349)
* Wasmtime's `Config::async_support` option is now removed and no longer
necessary. Embeddings can likely just remove turning this on and everything
should keep working like normal.
[#12371](https://github.com/bytecodealliance/wasmtime/pull/12371)
* Wasmtime now supports `Config::concurrency_support` as a knob to enable or
disable `*_concurrent` APIs at runtime when the `component-model-async` crate
feature is enabled.
[#12416](https://github.com/bytecodealliance/wasmtime/pull/12416)
* The `post_return`-style functions in Wasmtime's API are now noops and will be
removed in the future.
[#12498](https://github.com/bytecodealliance/wasmtime/pull/12498)
* Translation of `global.get` of a defined, immutable global is now turned into
a CLIF constant.
[#12234](https://github.com/bytecodealliance/wasmtime/pull/12234)
* The `wasmtime-wasi-nn` crate's dependency on `ort` has been updated.
[#12162](https://github.com/bytecodealliance/wasmtime/pull/12162)
* Error bounds requiring using `hyper::Error` in `wasmtime-wasi-http` have been
relaxed to taking `E: Into<ErrorCode>` instead.
[#12227](https://github.com/bytecodealliance/wasmtime/pull/12227)
* The `cranelift-assembler-x64`, and `cranelift-isle` crates now supports
no\_std targets. The `cranelift-codegen` crate now mostly supports no\_std,
but not entirely.
[#12222](https://github.com/bytecodealliance/wasmtime/pull/12222)
[#12235](https://github.com/bytecodealliance/wasmtime/pull/12235)
[#12236](https://github.com/bytecodealliance/wasmtime/pull/12236)
* Android release binaries are now compiled with a larger page size configured.
[#12246](https://github.com/bytecodealliance/wasmtime/pull/12246)
* Implicit binds are now allowed for WASIp3 sockets.
[#12225](https://github.com/bytecodealliance/wasmtime/pull/12225)
* Wasmtime's implementation of component-model-async now correctly checks for
whether tasks are allowed to block in all guest-to-guest situations.
[#12282](https://github.com/bytecodealliance/wasmtime/pull/12282)
* The `wasmtime-wasi-tls` crate now has an OpenSSL backend.
[#12228](https://github.com/bytecodealliance/wasmtime/pull/12228)
* Wasmtime's `OutOfMemory` error now keeps track of the attempted allocation
size that failed.
[#12351](https://github.com/bytecodealliance/wasmtime/pull/12351)
* Wasmtime's `*_unchecked` functions now work with `MaybeUninit<ValRaw>` instead
of `ValRaw` directly.
[#12366](https://github.com/bytecodealliance/wasmtime/pull/12366)
* Wasmtime now requires Rust 1.91.0 to compile.
[#12392](https://github.com/bytecodealliance/wasmtime/pull/12392)
* Wasmtime's management of component-model-async tasks is now consistently done
in all boundaries between guest/host tasks.
[#12379](https://github.com/bytecodealliance/wasmtime/pull/12379)
### Fixed
* The `HeapType::matches` implementation for `NoExn` has been fixed.
[#12350](https://github.com/bytecodealliance/wasmtime/pull/12350)
* Enum discriminant validation for composed components has been fixed.
[#12356](https://github.com/bytecodealliance/wasmtime/pull/12356)
* Shifts in some situations on aarch64 with Winch have been fixed.
[#12501](https://github.com/bytecodealliance/wasmtime/pull/12501)
* Debug value locations around cold blocks have been improved.
[#12484](https://github.com/bytecodealliance/wasmtime/pull/12484)
* Panics when adding too many headers to a `wasi:http/types.fields` has been
resolved
[GHSA-243v-98vx-264h](https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-243v-98vx-264h)
--------------------------------------------------------------------------------
Release notes for previous releases of Wasmtime can be found on the respective
release branches of the Wasmtime repository.
* [41.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-41.0.0/RELEASES.md)
* [40.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-40.0.0/RELEASES.md)
* [39.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-39.0.0/RELEASES.md)
* [38.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-38.0.0/RELEASES.md)
* [37.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-37.0.0/RELEASES.md)
* [36.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-36.0.0/RELEASES.md)
* [35.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-35.0.0/RELEASES.md)
* [34.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-34.0.0/RELEASES.md)
* [33.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-33.0.0/RELEASES.md)
* [32.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-32.0.0/RELEASES.md)
* [31.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-31.0.0/RELEASES.md)
* [30.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-30.0.0/RELEASES.md)
* [29.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-29.0.0/RELEASES.md)
* [28.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-28.0.0/RELEASES.md)
* [27.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-27.0.0/RELEASES.md)
* [26.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-26.0.0/RELEASES.md)
* [25.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-25.0.0/RELEASES.md)
* [24.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-24.0.0/RELEASES.md)
* [23.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-23.0.0/RELEASES.md)
* [22.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-22.0.0/RELEASES.md)
* [21.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-21.0.0/RELEASES.md)
* [20.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-20.0.0/RELEASES.md)
* [19.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-19.0.0/RELEASES.md)
* [18.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-18.0.0/RELEASES.md)
* [17.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-17.0.0/RELEASES.md)
* [16.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-16.0.0/RELEASES.md)
* [15.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-15.0.0/RELEASES.md)
* [14.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-14.0.0/RELEASES.md)
* [13.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-13.0.0/RELEASES.md)
* [12.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-12.0.0/RELEASES.md)
* [11.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-11.0.0/RELEASES.md)
* [10.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-10.0.0/RELEASES.md)
* [9.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-9.0.0/RELEASES.md)
* [8.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-8.0.0/RELEASES.md)
* [7.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-7.0.0/RELEASES.md)
* [6.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-6.0.0/RELEASES.md)
* [5.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-5.0.0/RELEASES.md)
* [4.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-4.0.0/RELEASES.md)
* [3.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-3.0.0/RELEASES.md)
* [2.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-2.0.0/RELEASES.md)
* [1.0.x](https://github.com/bytecodealliance/wasmtime/blob/release-1.0.0/RELEASES.md)
* [0.40.x](https://github.com/bytecodealliance/wasmtime/blob/release-0.40.0/RELEASES.md)
* [0.39.x](https://github.com/bytecodealliance/wasmtime/blob/release-0.39.0/RELEASES.md)
* [0.38.x](https://github.com/bytecodealliance/wasmtime/blob/release-0.38.0/RELEASES.md)
* [0.37.x](https://github.com/bytecodealliance/wasmtime/blob/release-0.37.0/RELEASES.md)
* [0.36.x](https://github.com/bytecodealliance/wasmtime/blob/release-0.36.0/RELEASES.md)
* [0.35.x](https://github.com/bytecodealliance/wasmtime/blob/release-0.35.0/RELEASES.md)
* [0.34.x](https://github.com/bytecodealliance/wasmtime/blob/release-0.34.0/RELEASES.md)
* [0.33.x](https://github.com/bytecodealliance/wasmtime/blob/release-0.33.0/RELEASES.md)
* [0.32.x (and prior)](https://github.com/bytecodealliance/wasmtime/blob/release-0.32.0/RELEASES.md)