bytecodealliance/wasmtime v40.0.4

on GitHub

40.0.4

Released 2026-02-24.

Changed

• Wasmtime's implementation of WASI now has the ability to limit resource
  consumption on behalf of the guest, such as host-allocated memory. This means
  that some behaviors previously allowed by Wasmtime can now disallowed, such as
  transferring excessive data from the guest to the host. Additionally calls to
  wasi:random/random.get-random-bytes, for example, can have limits in place
  to avoid allocating too much memory on the host. To preserve
  backwards-compatible behavior these limits are NOT set by default. Embedders
  must opt-in to configuring these knobs as appropriate for their embeddings.
  For more information on this see the related security advisory with further
  details on knobs added and what behaviors can be restricted.
  GHSA-852m-cvvp-9p4w

Fixed

• Panics when adding too many headers to a wasi:http/types.fields has been
  resolved
  GHSA-243v-98vx-264h

• Panic when dropping a [Typed]Func::call_async future.
  GHSA-xjhv-v822-pf94