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Fencer Intel
medium 5.7

CVE-2026-115892 json

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

published 21d ago modified 11d ago also EUVD-2026-109187 , GHSA-9pvw-hwfg-92h5 , RUSTSEC-2026-0378

cvss
5.7
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 37%
public exploits
0
none known

Summary

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.

Patch / fix

  • crates.io wasmtime 48.0.7, 49.0.4
  • bytecodealliance wasmtime 48.0.7, 49.0.4

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-115892 updated cvss 5.5

wasmtime: Wasmtime: Denial of Service via missing payload type validation in guest returns

  • Red Hat Connectivity Link 1 rhcl-1/wasm-shim-rhel9 Red Hat Enterprise Linux 10 tree-sitter 0.23.0-3.el10, virt-firmware-rs 26.4-1.el10
    affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
11d ago

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 5.7 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
CNA 4.0 5.7 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
crates.io wasmtime
>=46.0.0, <48.0.7
>=49.0.0, <49.0.4
48.0.7
49.0.4

Affected products

  • bytecodealliance wasmtime

Classification

Weakness
  • CWE-843 Access of Resource Using Incompatible Type
  • CWE-248 Uncaught Exception

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.