A flaw was found in Wasmtime. A malicious WebAssembly guest can cause a Denial of Service (DoS) by triggering an unhandled host runtime panic. When handling asynchronous streams or futures exchanged between the host and guest, Wasmtime fails to properly validate payload data types upon their return. An untrusted guest can exploit this behavior by manipulating return values with mismatched types, causing the host application to terminate unexpectedly.