Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type
Impact
Wasmtime versions 46.0.0 to 48.0.7 and 49.0.0 to 49.0.4 have a weakness where a malicious guest can cause the host to panic by passing a type-erased value to a guest expecting a different payload type. The host must have access to the guest code. The stated impact is a panic of the Wasmtime host.
Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.Affected packages
Affected products
Vendor version evidence. Product records are separate from automatic dependency matching.
bytecodealliance · GitHub_M
wasmtime
2 ranges
bytecodealliance · GitHub_M
wasmtime
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affected
>= 46.0.0, < 48.0.7
>= 49.0.0, < 49.0.4
Other versions: unknown
Original source 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.
Inside the record
Evidence available
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Original records
CVE-2026-115892View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.
cve.new JSON →Underlying weaknesses
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Contributing organizations · 2
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