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OpenAdvisories
Medium · 5.7 CVE-2026-115892 EUVD-2026-109187GHSA-9pvw-hwfg-92h5RUSTSEC-2026-0378

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

Published Oct 23, 2026 · Updated Oct 29, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
bytecodealliance wasmtime >= 46.0.0, < 48.0.7, >= 49.0.0, < 49.0.4 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Ubuntu 26.10 rust-wasmtime No fix yet —
Ubuntu 26.04 LTS rust-wasmtime No fix yet —
Ubuntu 24.04 LTS rust-wasmtime No fix yet —

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling wasmcloud 2.10.3-r3 —
Wolfi rolling yara-x 1.22.0-r1 —
Wolfi rolling zed 1.24.4-r1 —

Affected packages

EcosystemPackageAffectedFixedRecord
crates.io wasmtime >= 46.0.0, < 48.0.7 48.0.7 GHSA-9pvw-hwfg-92h5
crates.io wasmtime >= 49.0.0, < 49.0.4 49.0.4 GHSA-9pvw-hwfg-92h5
crates.io wasmtime >= 46.0.0, < 48.0.7 · >= 49.0.0, < 49.0.4 48.0.7, 49.0.4 RUSTSEC-2026-0378

References