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Medium 5.7Published Oct 23, 2026

CVE-2026-115892Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type

Updated under an hour ago ()

Does this affect you?

It affects bytecodealliance wasmtime. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
5.7 MEDIUM (v4.0, CNA)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
Weakness (CWE)
CWE-843, CWE-248
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Deferred
Record last updated
Oct 23, 2026
First seen by InfoSec Signals
Oct 23, 2026

Affected products

Affected products
bytecodealliance wasmtime
bytecodealliance:wasmtime (from the name)
from 46.0.0, < 48.0.7; from 49.0.0, < 49.0.4
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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