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[ CVE-2026-115892 · Published 23 Oct 2026 ]

Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type

CVSS 5.7 EPSS <1%Fix available

[ Description ]Official description

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.

[ Fixes ]Fixes and patches

  • wasmtime 48.0.7Fixed version · GitHub Advisories · rust package wasmtime: upgrade to 48.0.7 or later (affected >= 46.0.0, < 48.0.7)
  • wasmtime 49.0.4Fixed version · GitHub Advisories · rust package wasmtime: upgrade to 49.0.4 or later (affected >= 49.0.0, < 49.0.4)

[ Packages ]Affected open-source packages

[ References ]References