Wasmtime Files

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