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.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-9pvw-hwfg-92h5 Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Sat, 24 Oct 2026 00:30:00 +0000

Type Values Removed Values Added
First Time appeared Bytecodealliance
Bytecodealliance wasmtime
Vendors & Products Bytecodealliance
Bytecodealliance wasmtime
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Fri, 23 Oct 2026 21:45:00 +0000

Type Values Removed Values Added
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.
Title Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type
Weaknesses CWE-248
CWE-843
References
Metrics cvssV4_0

{'score': 5.7, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-23T21:26:54.528Z

Reserved: 2026-10-23T19:37:27.176Z

Link: CVE-2026-115892

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-23T22:16:58.633

Modified: 2026-10-23T22:16:58.777

Link: CVE-2026-115892

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-23T21:26:54Z

Links: CVE-2026-115892 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-24T00:00:17Z

Weaknesses