Most recent entries from all

fkie_cve-2026-115892

Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or an equivalent typed reader. A malicious guest that controls exported function types or returned values can cause the host to pass the type-erased value to a guest expecting a different payload type, which panics the Wasmtime host. This issue is fixed in versions 48.0.7 and 49.0.4.

GHSA-9pvw-hwfg-92h5 — Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type

Affected: crates.io: wasmtime

### Summary

Wasmtime may panic when the host lowers a component model `stream` or `future` into a guest, if the host created that stream or future with one payload type and the guest expects a different one. This can happen when an embedder creates a stream or future, passes it through a guest, receives it back under a type-erased type such as `StreamAny` or `FutureAny`, and then passes it to a guest function with a different payload type.

GHSA-63h4-6cx9-pjfj is a related advisory also fixing issues within this area, and this advisory is being issued for portions of Wasmtime that were not fixed as part of that advisory.

### Impact

This affects embedders that do all of the following:

1. Create streams or futures on the host with `StreamReader::new` or `FutureReader::new` 2. Pass them to guest code and receive them back as `StreamAny`, `FutureAny`, `Val::Stream`/`Val::Future`, or a typed reader whose payload is one of these. 3. Pass them on to a guest function whose `stream` or `future` payload type differs from the type the host created them with.

A guest can cause the mismatch in step 3 when it controls the types of the functions it exports or of the values it returns. In that case a malicious guest can make the host panic, a denial of service. Embedders that only use statically typed `StreamReader<T>`/`FutureReader<T>` with concrete payload types throughout, or that never pass streams or futures they created through a guest and back, are not affected.

RUSTSEC-2026-0378 — Panic lowering a host-created component model stream into a guest that expects a different payload type

Affected: crates.io: wasmtime

This is an entry in the RustSec database for the Wasmtime security advisory located at https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-9pvw-hwfg-92h5 For more information see the GitHub-hosted security advisory.

UBUNTU-CVE-2026-115892

Affected: Ubuntu:24.04:LTS: rust-wasmtime, Ubuntu:26.10: rust-wasmtime, Ubuntu:26.04:LTS: rust-wasmtime