Download Wasmtime 44.0.0

44.0.0
Released 2026-04-20.
Added
- The wasmtime CLI now supports a -g flag which runs a built-in wasm program
to host a gdbstub-compatible server (can be connected to with LLDB) to debug
guest programs.
#12756
#12771
#12856
#12859
- Wasmtime now has experimental support for the map<K, V> type in the
component model.
#12216
- Wasmtime's C API now supports wasm tag types.
#12763
#12803
- Wasmtime's C API now supports exceptions.
#12861
- Wasmtime's C API has more support for the GC proposal.
#12914
#12915
#12916
#12917
- An initial implementation of the wasi:tls proposal for the 0.3.0-draft
version has been added.
#12834
Changed
- The demangle Cargo feature of the wasmtime crate is now compatible with
no_std targets.
#12740
- The wasmtime-wasi-tls-* crates are now merged into one crate with feature
flags for each backend.
#12780
- Wasmtime now requires Rust 1.92.0 or later to build.
#12828
- The cranelift-codegen crate now compiles for no_std targets.
#12812
- The csdb instruction, a defense-in-depth measure for spectre, is no longer
emitted by default on aarch64 to match what peer runtimes are doing. In some
situations this is known to provide up to a 6x performance boost on macOS as
well.
#12932
Fixed
- Wasmtime's native DWARF has been improved on aarch64 to support recovering
values more frequently.
#12779
- A significant number of minor issues have been fixed throughout this release.
In addition to the security advisories found by LLMs there have also
been a large number of other issues identified as well. Many minor fixes are
present in this release for various situations for issues found in this
manner.